


Toujours Pur

by freefan1412



Category: Harry Potter - J. K. Rowling, 憂国のモリアーティ | Yuukoku no Moriarty | Moriarty the Patriot (Manga)
Genre: Alternate Universe - Hogwarts, Brotherhood, Crossovers & Fandom Fusions, F/M, First Meetings, Friendship, Gen, Lies, M/M, Manipulation, Muggle John Watson, Murder, Non-Chronological, Sherlock's obsession with William, Unresolved Emotional Tension, Unresolved Sexual Tension, chapter count increases as inspiration strikes
Language: English
Status: In-Progress
Published: 2020-11-15
Updated: 2021-01-08
Packaged: 2021-03-09 19:40:58
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 11
Words: 29,442
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/27581501
Author URL: https://archiveofourown.org/users/freefan1412/pseuds/freefan1412
Summary: The First Wizarding War was still raging when the only three survivors emerged from a fire that devastated the pureblood House of Moriarty. There is a society to change, and for that, some people have to die.
Relationships: Albert James Moriarty & Louis James Moriarty & William James Moriarty (Yuukoku no Moriarty), Moriarty Team, Sherlock Holmes/William James Moriarty (Yuukoku no Moriarty)
Comments: 78
Kudos: 146





	1. just one out of many

**Author's Note:**

> I've been obsessing over Moriarty the Patriot this past week and because I lack any and all kind of confidence to portray Victorian England, I went with a traditional Harry Potter Fusion/Hogwarts AU instead. 
> 
> _Caution_ : As I am up-to-date with the manga, by which I mean chapter 53, be aware that regarding the character interpretations, there may be some spoilers. 
> 
> About this fic: It is intended to be a drabble series, but since I don't want to make _any_ kind of commitment, it is marked with a finished chapter count and will stay that way even as more chapters are added in time.

**Notes for the Chapter:**

> CW: Murder, Attempted Murder, Pre-emptive Murder (wow, what a list)

The mansion stood dark and untouched. Dark clouds curling in the sky hid moon and a rushing wind hinted at coming storm. An ornate fence circled the property, the metal reinforced with ancient wards and unbreachable to those not permitted entry. The rustling of the trees that pressed up against the fence on all sides was loud enough to hide any whisper of swirling cloaks and hissed spells.

Argo Pyrites tested the wards, wand flashing in his hand. “The wards are as promised.” His assessment caused his comrades to shift, thrumming, adrenaline fuelled wary anticipation being shot through by excitement and something darker, something more…thrilling.

Four cloaked figures slipped through the fence as though it didn’t exist, the ornate bars curving around them. In a glimpse of moonlight, skull-like masks gleamed like bare bone, shadows chasing grotesque expressions over them.

The figures hushed towards the mansion, the wet, squelching earth giving away under their feet causing more than one of them to swear before they finally made it to paved ground where they cleaned their feet with impatient, intolerant swishes of their wands.

The double-winged front door swung in without a sound at the barest tinkering, just like the wards, and let them in.

“Split up, as agreed,” he hissed to his companions. “We’ll meet in front of _that_ room.”

In the hoods, signs of acknowledgement were barely visible, but they were not amateurs. The plan had been discussed well ahead of time. Everyone knew what to do. 

Pyrites headed down one corridor, wand waving the doors locked and silenced. Nothing was to wake in this house, not even a spider behind a curtain, that was not meant to be woken. His route carried him down the mansion, into the most remote part of it, until he stood before a door so small that a man of his build would ordinarily not even see it, even were it not enchanted to be overlooked. Knowing the door’s location however rendered these comforts null.

Wand lifting, the small door folded itself into the wall and revealed three cots, too small for even children to sleep in. Yet they were occupied, the sound of the occupants breathing invasively loud. The man’s sleeve slid soundlessly through the air as he pointed the tip of his wand at the room, tip lighting up with the power that was focused on the upcoming spell.

“Somnum.” Immediately after, he cast an amplifier to circumvent the house elves’ natural resistance against human magic. With that, the deformed servants seeing to all matters pertaining the household would not rouse should the wards alert them, and not even should one of the occupants specifically call them for….assistance.

The most important preparation done, the man finally allowed himself a sharp, triumphant smirk, secure in the knowledge that they now could no longer be stopped. The confidence perhaps slowed his steps on the journey to the targeted room though eager anticipation set his blood thrumming.

Despite the fact that the man’s route should have taken him the longest of them all, when he arrived in the target area, he was alone.

Pyrites frowned beneath the mask, lips thinning in displeasure.

Then, he saw the thin light of gold glimmering from the slit beneath the door.

The target was awake? Impossible, at this time of the night –

“Please excuse the confusion, Mr. Pyrites,” a voice suddenly said, appearing out of nothing right beside him. Speaking lowly _into his ear_. A sharp grip and twist on his wrist as he whirled forced him to drop his wand before he could even properly turn. The sound of it hitting the ground never followed. Pyrites swallowed. Digging into his back was unmistakably the tip of the stranger’s wand, locking him as surely as he had been cursed. “As your companions arrived ahead of yourself, it would have been rude to keep them waiting outside.” The speaker withdrew slightly, giving the impression that he straightened his back formally. “On behalf of the young masters, I am pleased to welcome you to Rockwell Manor. Please enjoy your visit.”

The door in front of Pyrites swung ominously open. It made no sound, ghosting over the lush carpet that stretched into a lavish, private room. A wide, four-poster bed seemed to take up the space of one half yet left the other untouched, curiously vacant seeming with empty walls and only a simple desk as furniture. A concession to the rules of the farce the Rockwell family had been forced to consent to.

While noticeable empty of furniture, there were more people than there should be. Even at daytime, it would have been unusual considering the nature and message this room sent.

Yet Pyrites was given no option but to enter, the wand at his back making as much clear.

The three occupants of the room, three children, were all looking in his direction with, somehow, unsettling smooth expressions. Pyrites had to swallow again as he was directed to stand in front of them. The respectable distance, the precise balance between being too far away to be observed and close enough to sully was easily recognizable and long familiar to a man who routinely knelt at just such a measured distance before a being who made others doubt his very mortality, who excluded such a presence that the unworthy and worthy alike hardly dared to raise their eyes to glimpse him.

To be presented in such a way before _children_ was at once ludicrous, insulting, and deeply presumptuous. The coldness in the children’s eyes, though, made something inside him shiver in a way that was at once also too familiar as well as displaced. It made him select his words carefully.

“How did you know?” Because at this point it was evident that the raid had been expected. Who was complicit? Had the Rockwell’s decided to brand themselves bloodtraitors as well? If so, they would be made to pay, even more than these children.

At the question, expressions flickered over the children’s faces, different on each, and though given the nature of things, it should be natural that the oldest spoke for all of them, it was a the middle one who’s perfect, doll-like smile parted.

He lifted a hand and from the sleeve of his almost stiffly formal jacket slid out a wand. Pointing it at Pyrites, he murmured with focused confidence, “Legilimens,” and Pyrites' heart jumped first with bemused confusion, then with sharp, bile-like dread when pressure focused between his brows and his perception narrowed down, against his will, to gold-framed ruby eyes.

 _Impossible_! His mind screamed, and yet here he was, immobile and trapped inside his own head. An elegant but inexperienced touch leaved through his mind like through a book – red eyes gleamed, penetrating, all-knowing – and Pyrites was forced to watch as every closely kept secret was torn from his scrambling grip and devoured by a demon.

As his loyalty was hollowed out, his blood slowly froze in his veins. The Dark Lord would not forgive this failure. Even as he thought this, he felt the intruder – the deliberate, methodical, cold-hearted way made it impossible to think of this…creature as a child – linger on it and explore the consequences as Pyrites knew them.

Something acid slid into the touch of the creature then, searing Pyrites with its pressure even as he was forced to bear witness as every moment of Pyrites service and the time he spent in the honor of the Dark Lord’s presence was painfully drawn out. Taken apart. Analyzed. Pyrites could not tell what this play of a noble pureblood child thought, but devilish as it was, he could still tell that it was thinking, even if the sheer ease with which it locked Pyrites into a tiny corner of his own mind was nothing short of terrible.

An even longer time was spent contemplating the plans they had made for this night; Intending to make an appropriate example of the mudblood unworthy of even licking the mud from the family that had taken him in, it was debated back and forth if they should include the true heirs of House Moriarty as witnesses. To teach them a lesson. To guide them back on the right path.

Touch like ice and fire carved though thoughts out of their place, arranged them in the limelight until the weight of them seemed unbearable.

When it was finally over, Pyrites’ skin was slick with cold sweat, his heart was pounding like a herd of centaurs’ in gallop against his ribs, and his breath care harshly as though his head had been locked into a bubble-head charm without air.

The devil in the form of a child merely looked pensive, turning his back on Pyrites without thought. “It’s as we suspected,” it said to the children, “The Rockwells indeed lowered the wards in exchange for Louis’ life.”

The youngest child pursed his lips. “What will we do, Brother William? Are we going to kill them?”

Slowly, William shook his head. “We would just be moved on to the next family of, as society claims, worthy status. Additionally, even if their deaths would not seem suspicious now, in the long term having the deaths of Mr and Mrs Rockwell occur so soon after Mr and Mrs Moriarty could draw undue attention. We will place them on the list.”

“That means Louis will have to endure their scorn on his own while we are at Hogwarts, Will. Are you sure that’s alright?” The heir of the House Moriarty, seated on a simple desk chair and still managing to radiate an aura of control and dignity, tilted his head in curiosity. “It wouldn’t be so hard to frame our uninvited guests.” He slid a sliver of a glance the man’s way, and the look in those moss green eyes was as though they glimpsed a something even lower than vermin despite not a muscle on that youthful face twitching.

William smiled, picture perfect but with a crinkle around his eyes that gave the expression away as genuine. “Louis won’t be alone, Albert. He has Jack.”

The oldest boy’s eyebrow ticked up, gaze darting to the man still holding their guest prisoner. He smiled, sheepishly apologetic in a way that seemed to wash the coldness out of his aura. “True, my apologies Jack. I redact my previous statement. At that rate, you and I will have to worry about Louis leaving us behind, Will, rather than the other way around.”

The youngest, Louis, looked down with a faint blush of pleasure on his cheeks while the one addressed as Jack chuckled gruffly. “No need to lay it on so sick, Young Master Albert. Rest assured, I will ensure that you will not fall behind. Both of you.”

“Ah…” said the boy, who was comfortably in the range of Hogwarts age, mildly, which could not succeed in hiding the way his face paled slightly.

William, even at this age never quite as easy to read as either of his already formidable brothers, merely chuckled lightly, a hand before his mouth. “If that is what we will be greeted with come morning, I suggest we move this matter along. Do we have one more set prepared?”

“But of course, Young Master William,” responded the only adult. A flash of light hidden by the press into fabric later and the uninvited guest was frozen still as a statue, finally allowing the man to step away from him. “I have already learned better than to think that you would err. I completed four sets the day you requested my aid in this matter.”

The middle child’s lips curled a hair higher, pleased, with a touch of benevolent approval. “Thank you, Jack.”

Waving a negligent hand in response, the man pulled a small object out of the pocket of his professional, traditional suit. Smaller than a finger, clinking metallically, and the reason why was not revealed until it was unshrunk. A pair of shackles hung from the man’s white-gloved hand, the cuffs themselves thudding into the carpet and while a gleaming ball of heavy iron was suspended in the air by the man’s other hand before it could damage the floor.

Smile remaining, William nodded satisfied. He and his brothers all worked together to get the cuffs around the man’s legs, even though each of them would have been capable of it on their own even with their still developing bodies. Yet they cooperated, Louis immediately taking the brunt of the weight with stubborn determination while each of his brothers picked up one of the dangling cuffs.

Louis managed to set the weight down on the carpet with a heavy huff and while he waited, raised his eyes to the frozen man whose fate was now literally being tied to it.

The eyes were bulging, whites prominent and seeded with terror-red veins. The shutdown struggle of the man’s body was instead warred in his eyes, dread and denial and fear for his life making him obviously rethink all his life choices.

But he was not given the opportunity to beg for his life.

Just as he would not have granted that chance to Loius.

In this mansion, even if the man could scream, no one would hear. No one would answer.

William must have seen something similar, because when he straightened, he said pleasantly, “There is no need to look like that, Mr. Pyrites. _We_ are not killing you, as your death in these halls, no matter how accidental, would be too implicating. A body would be...troublesome.” The logical reasoning paired with his calm face and youthful features were unsettling to anyone who had not already offered their lives to him to behold. The red eyes, a shade so rare even in magical bloodlines, seemed to glow with an internal light that offered at once condemnation and salvation. “Instead, I think you will find that merpeople are not quite so repulsive as you think them when having gills would preserve your life.” William smiled, sweet and well-mannered, the same smile he would offer over tea. There was nothing to in his expression or demeanor to belie this. It seemed, impossibly, that he was entirely sincere.

“Goodbye, Mr. Pyrites. To answer your last wish of ‘why,’ allow me to inform you that we, James Moriarty, are delivering judgement upon you on behalf of beings other than those you deem worthy by the arbitrary luck of birth.” Whereas Loius and Albert took a few steps back, Albert reclaiming his seat on the chair, William remained standing close, head tilted up to meet eyes in which, far too late, an almost mindless sort of awe joined the still dominant terror.

William James Moriarty was the sort of person who could inspire exactly that kind of combination merely by revealing himself. Only few had what it took to endure those contradicting, powerful impulses he inspired, and those who did would be loyal to the end.

Pyrites, Stunner worn off now, did not belong to those people. He, faced with a supremacy and majesty of the likes that even his Dark Lord on his throne of bones could not reach, forgot what last words he had to say.

And then a jerk behind his navel and –

Only cold, and wet, and darkness –

A devil, a demon, a savior, a god in human form come to pass judgment upon those unworthy. Regardless of the ocean water flooding his lungs, Argo Pyrites laughed, for he knew nothing could stop the inevitable.

**Notes for the Chapter:**

> Argo Pyrites is from JKR's drafts. He may have been an alchemist, he may have been a Death Eater, or both. In any case, he's a convenient no-name character to be killed off in the first chapter.


	2. a fated meeting - kid edition

They first saw each other the day many people made new friends and acquaintances for a lifetime.

In that instance, and in that instance alone, they were not so different from any other child.

Sherlock Holmes’ gaze swept over platform 9 ¾ with sulky grouchiness that could singularly attributed to the fact that it was his _brother_ who delivered him here and not his mother, for whom, as a muggle, the current political climate was too dangerous to step into magical public space.

Families, those not convinced of their safety as due to their political leanings, were reluctant to part and had stalled for as long as possible, which meant that now, five minutes before departure, the platform was still bursting with people.

And yet, even still. Sherlock's scan stalled on him. On the single instant he glimpsed him through the moving crowd.

Though he was young, he was still a genius of the Holmes family, and even at eleven years old, it took him no more than the span of a heartbeat to categorize his observations, to organize his thoughts, and to draw the logical conclusion.

He had not looked away from that precise direction and when the crowd parted for a moment again, ruby red crimson eyes gazed back at him from a face that was set in a precise, polite version of puzzlement and curiosity as though perplexed by the - instant! - of scrutiny from across a bustling platform.

Sherlock, one track mind and obsessive curiosity sweeping everything else from his mind, had already taken half a step in that direction before his brother’s hand clamed down on his shoulder like a vice grip. “Don’t dawdle.” Despite being impatient and controlling as ever, not even Mycroft could claim to be unaffected by the tension ruling any gathering of more than a handful of people. His tone today was especially clipped and the corners of his eyes tight.

“I’m not. What are you even doing here, Mycroft. I get can on the train on my own. Don’t you have important work at the ministry to do?”

His brother slid him a sharp look and rudely dragged him along. “I do, in fact have more important things to do,” he said once he’d maneuvered Sherlock to the train. “However, for mommy’s peace of mind, I promised her I’d personally see you to the train. Get on.”

Sherlock glared and sulked some more. How unfair was it that Mycroft was always brought to the Hogwarts Express by their mother and now that is was Sherlock’s turn, he had to settle for _Mycroft_.

But anyway, a glance in the direction of the front of the train revealed that, as far as he could see, the strange boy had already vanished, so there was no reason to endure Mycroft’s control freak nature any more.

Tossing his weightless luggage into the train in front of him, Sherlock hopped on. “Whatever. I’ll be home for Christmas. How about you do something about all of _this_ by then.” Though it was clear what he meant, even Sherlock knew better than to speak about politics more explicitly. A certain amount of arrogance may be inherent in being always the smartest person in any room (current company excluded), but being smarter than a dozen adults put together did not make anyone invincible. “Mommy’s troubled by it.”

Mycroft shot him a sour look, just this side of dry. “Don’t make trouble.” With an imperious swish of his cloak, he strode off, having fulfilled his promise to the letter.

Huffing, Sherlock hauled his luggage through the train, looking for a compartment whose company would not lower his IQ by proximity, and if he kept an eager eye out for sunshine gold and ruby red that could stare with such fascination at a mechanical engine despite being dressed in all the hallmarks of pureblood nobility, then that was no business but his own.

.

They first properly met in front of a glittering black lake. A majestic castle rose above it and went ignored since for Sherlock, there was no question what was more worth his while. 

He paid no attention whatsoever to the social etiquette that would judge him for barging in and inserting himself into the bubble of tranquil space the boy had so _beautifully_ artificially projected around himself in such a subtle way that standing slightly apart in solitary silence seemed elegant instead of arrogant. Sherlock had to take a moment to admire the sophistication of this social avoidance tactic. If he could make people come across as rude for approaching him, he would be doing that every hour of the day.

Sherlock for his part did not consider himself rude. After all, it was not him this dignified aura of please-remain-at-a-distance was directed at. And wasn’t that just _fascinating_ of a pureblood scion, even as it fit into the profile Sherlock had already started to build from that first glance at the train station.

So Sherlock elbowed some nameless snob he couldn’t bother to remember out of the way and claimed the other spot in the tiny boat that was to carry them across the lake.

Already he could tell that it would be soooo worth it, for there was _nothing_ on the boy’s face that slipped from a mask of polite attention despite Sherlock's actions, which told Sherlock quite clearly that that expression – an expression that should be casual or excited given the example their year mates provided – was deliberately and closely controlled. Even now, even here. 

Why go to such lengths? The answer was obvious: there was something that other people should not see.

Grinning, Sherlock gave the other boy another once over, just to confirm, and waited impatiently for the boats to depart from the shore so that they could start the real conversation without risk of being overheard. The other boy watched him back, mien still so very perfectly arranged, but Sherlock could feel the scrutiny he was exposed to in turn like goosebumps over his skin.

“I was looking for you on the train,” he found himself saying despite himself, an itch under his skin rendering him unable to remain silent. A golden eyebrow arched, the appropriate response for being told such a thing by a stranger whose name you did not even know. “I wanted to talk to you.” He leaned forward, his grin widening, _needing_ to get a better angle for observing the other in this lantern-lit night.

However, no matter how closely he observed, the expression shifted merely into one of soft, polite confusion, the boy’s hands remaining gracefully folded in his lap. _Sherlock Holmes_ got nothing from him, and wasn’t that _something_.

“I’m sorry, have we met?” The boy’s voice was a smooth, pleasant timbre, his intonation lilting with the perfectly polite question. It was a quiet voice; not the sort that needed to be raised to be heard but instead one where people quieted to listen and that was easily blended with a more subtle sort of charisma.

Sherlock made the split second inference that, clearly, the boy already knew how to wield both and noted interestedly that he used it to not present himself as the center of attention as most would but as someone who blended into the masses instead. As someone who was not at all extraordinary. Even though if people only _opened their damn eyes_ , they would see how very wrong that very notion was.

And _oh_ , thought Sherlock, was it going to be like this? For an instant he couldn’t tell if he was frustrated or thrilled. Thrill won out in the end because it doubled his gain – one the puzzle, two the triumph of each morsel he picked out and set into its place even if it cost him in this moment…something.

“Depends on how you define meeting,” replied Sherlock, waving a flippant hand. “I would say we did, though. After all, you _noticed_.”

A slight crease formed.

Sherlock took a moment to admire how perfectly timed this expression was. How perfectly manufactured he had a feeling _everything_ about this boy was, and it made him want to pick at the edges and corners (once he _found_ them) to glimpse at what laid beneath. What would it take?

(His initial fear that Hogwarts was going to be as dreadfully boring and stupefying as people in general tended to be was all but forgotten, just like Hogwarts itself and the company social norms said they should be keeping. Sherlock, when he was absorbed by something, focused on that to the exclusion of everything else, much to his brother's frustration.)

“Pardon me, I’m afraid I do not know what you are talking about,” the other boy deflected. “What is it that you claim I noticed?”

Sherlock’s lazy grin gained a sharp edge. “You noticed me observing you. On a crowded platform, in the bare few moments that you had.” 

A slow blink, a slight tilt of a head in confusion, an introspective furrow of his brows. “I’m afraid I still don’t know what you are talking about.”

What a perfect, unassuming liar. Sherlock’s fingers tapped against the side of the boat in restless delight, barely managing to hide it, which he had to, because this was the sort of game they were playing now, right? Never show all your cards.

A small jolt went through the boat, finally setting it off from the shore. It isolated them splendidly over open water, the lapping of small waves against the bow of the boat just loud enough to blur their voices if they were careful about it. Of course, it helped that everyone else was absorbed by the excitement of finally arriving at the fabled school. But what sort excitement was that, when the school would be there for the next seven years while this moment was as difficult to grasp as a silhouette in mist.

“You want to know what _I_ noticed?” Sherlock asked lowly, teasing with a smug curve of his mouth. “I saw a pureblood from a well off, ‘traditional’ family admiring the one piece of purely muggle engeneering on the platform.” He leaned forward conspiringly, whispering, “You’re a muggle enthusiast, aren’t you? No, more than that. You’re interested in their _science_ , aren’t you, because that is the only thing that was unique about that engine,” and had the great satisfaction of, for the first time, watching that mask _slip_.

Just for an instant. In any worse light, for anyone watching less closely than Sherlock, it would have been invisible. But it _was_ there, the slightest hint that Sherlock hit something. The boy didn’t do anything as obvious as widening his eyes, as freezing, or god forbid staring at him. No, the only thing that confirmed Sherlock’s suspicion for was the way he suddenly felt…bare. Exposed. _Seen_. As if the focus on him finally narrowed to the blade Sherlock had known it could be. 

Sherlock's smirk widened. “And that is not only unusual even for muggle enthusiasts. For someone of your blood status, that would become a target on your back. That’s why you’re hiding it,” he finished, sure that he was right about the last bit as well even if not as sure as he was about his other conclusions. Silence crept in after the last word finished fading away. A subtle charge electrified the air and Sherlock _reveled_ in it, in this challenge of a game, in this anticipation as he waited for the other’s move.

The boy’s gaze dropped from his after a moment, flickering in a deceptively casual way out over the water as he leaned one arm on the side of the boat, relaxing his stiff posture slightly. Though he wore a smile on his face and curiosity was shining in his eyes, there was still something so incredibly meticulous about it that a spider’s honeyed web would have seemed less like a trap. “How did you know that I am from a pureblood family?” was the nothing-saying reply, and who was Sherlock to deny an invitation so personally arranged, just for him.

“Demeanour – the lack of fear specifically, which tells me you’re from a family that doesn’t need to fear the current political climate, which in turn is only a very select group. The quality of your outfit, specifically the fact that you wore a specifically tailored cloak, despite your age. The fact that you knew to hide your interest in mechanics.” Sherlock scoffed. “It’s a deduction based on simple observation. Anyone could tell as much if only they _looked_.”

The boy hm-ed, a very thoughtful yet almost amused sound. It was designed to seem as though Sherlock was only being politely humored. “The problem being that few people look.”

“Exactly!” Sherlock snapped his fingers at him, ignoring the undertone that was supposed to discourage him from this conversation, except not _really_. “I _knew_ you’d get it.”

“Then allow me to return the favor,” the boy suddenly smiled, and oh, what a smile it was, making Sherlock straighten his back and freezing him in place, mouth half open as he forgot what he wanted to say, so entirely taken aback he was by that sly, confident curl a mouth shaping that kind of declaration. And that was before the boy even _began_. “You are a half-blood, your mother being a muggle and your father likely a pureblood. You spent your time seeking distractions from your constant observations. You prefer intellectual pursuits in even this, however, which is why you are widely read as well as perpetually bored by those who cannot keep up with you. You play the violin, likely as a means to calm your mind and control your impulses.” The boy’s smile curved just the right amount as he asked lowly, “Am I wrong?” in such an obvious, humble ploy for affirmation that it could not be anything but a front to disguise how utterly _sure_ he was.

Sherlock leaned back, feeling as though being too close would burn him, which should not be as exciting as it was, even as he was shocked into a startled bark of laughter. “How’d you know?”

There was a glint, so barely, _barely_ there in the ruby eyes that Sherlock thought he was not meant to see it at all, but he did, and he could not unsee it for the life of him.

“That much is evident,” the boy only said.

Sherlock's own words rephrased back at him. In a _perfect_ display of sly wit and shrewd cleverness.

And Sherlock. Well. Sherlock thought this had be fate. What prefect manners? What perfect demeanor? _Everything_ about this boy was _perfection_ _incarnate_ , as if he’d been born to destroy the very notion of boredom in Sherlock’s life! He laughed aloud, could not help it, had to hold his stomach as he started to gasp for air, and still noticed nothing of the weird looks their boat was garnering from the others, too delighted by the genuine bafflement he _thought_ he could glimpse in the only eyes he wanted on him.

Unfortunately however, the world still moved on its own and their boat towed itself to the dock at the foot of the castle before Sherlock could take some more delight in -

“We’ve had such an enlightening conversation,” the boy stated once he’d climbed out, steadily gazing back down into the boat at Sherlock. The flames of the lanterns chased shadows across his features, deepening them, sharpening them, made his hair glow with a touch of orange like molten gold. It cast a light into his eyes that seemed to shine internally with something impossible, something unknowable, and the way Sherlock’s heart leaped left no doubt that this _had to be_ _fate_. “And yet I don’t even know your name.”

Sherlock climbed out with a bounce in his movement, regaining equal eye-level. All the while he felt attention on him that _saw_ him. That could pick him apart, if he wasn’t careful, in the very same way Sherlock could take others part. It was the first time he felt like this and he knew, with great enormity, that his was a sensation he would be chasing for the rest of his life.

“I’m Sherlock.” He held out his hand. “Sherlock Holmes.”

Without a moment of hesitation, the other took it, maintaining the contact then _just_ the appropriate amount of time before letting his hand fall by his side again. “I see.” The keeper of the grounds called for them, the others already having ascended the stairs. Neither of the boys turned a hair into their direction, though, only focused on each other. A faint, knowing smile quirked the other boy’s lips. “In that case, it is nice to meet you. I do believe however, we are keeping our future classmates waiting, Mr Holmes.” With that, he smoothly turned to walk up the stairs.

Just like that. Leaving Sherlock standing there stupidly.

“Hey, wait!” He shouted, indignant, and hurried to catch up. “You haven’t told me _your_ name yet!”

**Notes for the Chapter:**

> First conversation on a boat? Check.  
> Introducing themselves by introducing the other? Check.  
> Identifying each other as a player of the same calibre? Check. 
> 
> Mirroring their first meeting in this AU was surprisingly easy. I didn't even plan on it, but I thought about when they could possibly meet each other first, and that that, given they are the same age, had to happen on September 1st. Political climate and their significantly younger age made it so that they couldn't talk upon first sight, but hey, such discovering such derivations are what's so much fun about writing AUs. 
> 
> Important to note, I think, is that at this point Sherlock meets someone equal before he had to find ways to come to terms and cope with being so _singular_. Thanks to William. Who's opinion about this was empathically _not_ asked. XD


	3. professorship

“Ah, welcome Mr. Moriarty,” greeted the most powerful wizard in the world amiably, the hem of his insistently orange-pink dotted cloak swishing as he gestured for his guest to take a seat. “Lemondrop?” The young man in question accepted the offered sweet with a smile and a polite expression of gratitude as he settled into a cushioned armchair, looking for all the world as though he belonged into the magical, organized disorder of the headmaster’s office.

Few people had the self-awareness and self-confidence to appear so entirely unfazed, yet despite his youth, William did not appear arrogant for it.

“I admit I was surprised to see your application on my desk,” Professor Dumbledore began, eyes twinkling brightly, “Forgive an old man’s memory, it feels like it was just yesterday that you walked out of these halls with full honors.”

The young man smiled modestly, gentle humor reciprocated. “You may rest assured, Professor. The graduation ceremony was indeed only last week.”

The professor chuckled. “Ah, so it was. And yet here you are again. Are you so fond of our beautiful school that you could not bear to part from it?”

“While Hogwarts is certainly one of a kind, I’m afraid my motivation for applying lies rather in the subject,” the young man replied, tone self-depreciating as if apologizing to the school. “I’m sure it does not surprise you, Professor Dumbledore, that Arithmancy holds some fascination for me.” At the understatement, the professor chuckled again. “Were I permitted to take up the professorship, the opportunity to enrich the field in a professional capacity would become available, so I could not pass up the chance to apply when I heard Professor Whitewood retired.”

The old teacher dropped his light air, inspecting the young man over his half-moon glasses as he picked out the part of that statement he sought to address first. “You believe you have something to contribute to the field? Arithmancy is, as you are aware, an old study. Centuries of scholars have already devoted their lives to it.” _Why you?_ was the question he was too well-mannered to voice directly.

Leaning back in the armchair, steepled hands resting on crossed legs, the young man’s ruby eyes sought the headmaster’s without flinching. “I believe that everyone has something to contribute,” he responded warmly, confidence unshaken by the implied doubt, “be it experienced wizards of renown or students receiving their first lesson.” The young man, still almost a boy, smiled with a tilt of his head. “Knowledge and research are not so easily quantifiably that they could be contained in books in their entirely, no matter how venerable the authors or old the discovery. Especially a theory heavy subject, such as Arithmancy, lives through discourse and exchange.” His lips curled more, knowing, and he conceded gracefully, “though to answer the question you had intended, Professor; I am indeed aware that my expertise in the subject eclipsed Professor Whitewood’s by the time I received my OWLs. As such, I do believe that I am indeed qualified for the position.”

Assessing look fading, Professor Dumbledore’s eyes regained their twinkle as he folded his bony hands below his chin. “That is a polite way of putting that you and your…rival, Mr. Holmes, may be singularly responsible for driving the good man into early retirement.” More than once had the elderly professor after all come to the headmaster in despair because the essays, carefully no longer than allowed, condensed such complex thoughts on a mere few feet of text that to decode them was to fill an entire book. Having such students could, the headmaster allowed, be quite a blow to one’s teaching confidence.

“Such was never the intent, though of course I don’t presume to speak on Mr. Holmes’ behalf,” deferred the applicant with a marginal dip of his head, appropriately apologetic. “I hope we did not cause Professor Whitewood too much trouble.”

“Oh, I dare say being kept on one’s toes is quite healthy for the spirit once you reach our age,” dismissed the headmaster brightly, smoothly neglecting the fact that few people could match him for eccentric taste. “Last I heard, good Wulfric sought to expand his horizon with herbology now. His wife’s garden could do with some attention, apparently.”

The applicant hummed, just the right of curious to seem interested and yet not so much as to encourage conversation in that direction. “Louis likes to care for our gardens. I never fail to be impressed by the complexities required to do so adequately. It should serve to keep Professor Whitewood busy, if that is what he seeks. I wish him the best. Herbology requires a sense for plants that I believe not everyone has and that can only be learned to a degree.”

An interesting point to mention, which brought them closer to the reason they were here in the first place. “And yet, could the same not be said for Arithmancy as well?” enquired Professor Dumbledore curiously. "How would you teach someone who does not have the aptitude for it?"

“People’s talents are many and varied. To attempt to fold the forms of aptitude organisms as complex as sentient beings can display into a mere dozen subject that can be taught in school is the height of folly. Therefore, having a talent for the few subjects that are institutionally recognized is the exception rather than the rule.” William titled his head curiously in turn, a subtle way of inviting the professor to argue the opposite. "Students learn as they do and what they do. It is the role of the teacher to provide means and support. To guide and motivate the learning process. Aptitude is welcome but not required." 

Albus, quite delighting in the discussion, though striving to hide it, hummed thoughtfully. “That is quite a liberate position, Mr. Moriarty.” Picking up a conveniently placed parchment, he made a show of skimming it though he hardly needed it as he had of course considered the potential colleague’s application letter quite thoroughly already. “I see here that while you intend to take up a full post here, you are also preparing to sign up for a muggle university.” Over the rim of his glasses, he offered the young man a look. “As admirable as your desire for knowledge is, as a teacher, the students must be your first priority.”

Again, William remained unfazed, self-confidence so deeply rooted that not even implied, however testing, censure from Albus Dumbledore could shake him. It was quite admirable how he managed to appear with a contained sense of self-awareness instead of upstart pride. If Sherlock Holmes sat in that chair instead of William Moriarty… Well, sufficient to say, it was not Sherlock Holmes who sat in that chair.

“I am, of course, aware of that,” responded the young man with an acknowledging dip of his head. “However, as an elective course, Arithmancy has on the average only half the classes Transfiguration does.” He smiled, vaguely self-depreciating and apologetic. “You asked if I could dedicate enough time to the students when I study on the side. My response is that if I want to give my students a comprehensive education worthy of the complex study of Arithmancy, then I am in fact _obliged_ to do as I plan to.”

The polite mask of humbleness, humored for Professor Whitewhood’s integrity as a teacher, fell away the longer William spoke and revealed both reflecting and critical thoughts he must have formed while sitting in those very same lessons. “Arithmancy is the study of numbers, of their relations, of the magical properties they can unfolded in different combinations. In other words, the very basics of the magical subject is pure mathematics. That is an area our non-magical sister society is _massively_ ahead.” William gave the headmaster a sly look, as though sharing a secret. “Mr. Holmes and I have based much of our research on the works of people such as Thales of Miletus and Isaac Newton, household names in non-magical societies all around the globe,” he informed, just in case Albus had not been aware.

The professor had in fact recognized those formulas, but only _just_. Anyone other than him would not have, which was precisely the point to make to illuminate how much potential was _wasted_ , simply because wizarding society as a whole considered muggles and everything they had to offer primitive. That was a fact not even the most muggle-enthusiast wizards could distance themselves from. The term ‘muggle’ itself already carried condescending connotations, and it did not escape the headmaster that the word had not been mentioned once in this conversation yet.

William was not done yet either, and though everything about his demeanor was classically, elegantly old pureblood, the thoughts he had were the furthest thing from, delightfully and radically so. “If our works kept giving Professor Whitewood trouble, then there you already have the answer regarding the _necessity_ of education in the non-magical discipline of mathematics,” he concluded his point, voice becoming softer. “No society stands still, yet that is precisely what this society’s outdated value system maintains for the sake of stability and safety, disregarding that only dynamic self-understanding allows a people to withstand and overcome upheaval. If this does not change, it will end in ruin.” As it almost did. 

Dumbledore considered him deeply, following that train of thought to its end. “The best way to induce peaceful change is through children. Is that where your interest in teaching stems from?”

“Partially,” admitted William freely enough, conceding that that kind of motivation may be a concerning point to consider in a potential teacher. “Installing and upholding values is part of a teacher’s responsibilities, yet that should never come at the cost of the children’s own ability to reflect.” Saying only this much in his own defence spoke clearly how much weight he ascribed to the point, however.

“…I assume I may take that under advisement to make Muggle Studies an obligatory subject,” Professor Dumbledore observed after a long, thoughtful pause, his voice lilting with quiet amusement.

This time, the young applicant however did not share his good humor, face smooth and expression mild for all that the look in his eyes was severe. “You may take that as a suggestion that Professor Burbage ought to perhaps make a more immersive study of her own subject,” he said, and stroked a strand of hair behind his ear, where it remained for just a moment as the young man titled his head in a way that radiated a strong opinion, almost to the point of challenge. “To speak bluntly, I find it inexcusable that the person responsible for teaching our children about our neighbours is unable to properly explain the concept of post stamps, which is the absolute basic knowledge necessary to communicate with non-magical individuals, never mind that even OWL students are barely able to use a telephone.”

Something about his demeanor, the choice of words, the hint of conviction in the tone made the professor pause and deliberately seek to meet those rare ~~unsettling~~ ruby eyes.

It occurred to him that he had perhaps taken the entirely wrong expectations into this interview.

A charismatic, young genius desiring to stay at Hogwarts after graduation was an uncomfortable parallel to someone who the professor felt they still had not seen the last of. A part of him had been wary of a repeat the moment he received the application.

He could see now that he should have been less worried about dark ambitions inspiring this passionate mind and more about being tested, himself.

William Moriarty was not wrong with his assessments, with none of them, and he knew it with the certainty of one whose intellect had never let him err before.

Dumbledore had often dwelled upon the shortcomings of their society himself, had traced misfortune and tragedies, his own included, back to the cracks that no one wanted to see.

Prejudice and casual superiority went hand in hand, could be found in every layer and too many members of their society. Again, even in himself, for all that he attempted to better himself.

This young man had now come here to apply for the Arithmancy professorship, and he sought it not for the prestige teaching at Hogwarts at such a young age would bring, or for the steady income, but as a means to better their society, starting with the children. Something, so the implication said, that he found the professor to have either been unaware of needing fixing or neglectful of.

Now, however, the fact that their society had deeply rooted social problems had been made explicit.

How Dumbledore responded determined his suitability for addressing those concerns in the eyes of William. Even if he personally agreed but professionally could not endorse such a position, he would fail the test.

The discussion this interview had become was not even about William’s possible employment. That was part of it, certainly, and still an option, but someone like William did not walk into a situation like this without several agendas.

As Albus himself should well know. 

Albert Moriarty was politically active in the ministry, a young, handsome, and popular voice that rose quickly through the ranks. If William joined him, Albus foresaw them exerting significant influence in the government sometime in the next five years. At first look, that would even be a more effective way to implement change, yet here the younger brother was, applying for a position at Hogwarts.

The scheme unfolded before him as he thought.

William Moriarty was not acting alone. His agenda was shared by his brother, most likely younger and elder both, and in that light, his presence here could be seen as a divide and conquer tactic. If Albus failed to be judged by these young futurists as a suitable head of the only school in Great Britain, he would gain himself a powerful political opponent who would strive to see him replaced with someone more…capable. More willing to change. 

As clever and ambitious as this plan seemed to be, it intimidated the professor little. The ministry was after all filled with his political enemies. One more would not make much of a difference.

However…

Albus Percival Wulfric Brian Dumbledore, with his often forgotten, controversial past, with his tendency to neglect the individual for the greater good understood William James Moriarty’s thoughts so well that it hurt.

It scared him too, to suddenly see a young version of himself sitting before him instead of the mirror of a young Lord Voldemort that he had suspected. For that reason, he should refuse the boy as firmly as he could. After all, Albus himself constantly toed a fine line between trusting and condemning himself. To trust that someone younger, more inexperienced, more innocent would find the same control Dumbledore required of himself was ordinarily not something he would even contemplate.

Yet at the same time, all of William Moriarty’s points _were_ valid and to act in the interest of common good rather than self-interest was in itself something that should be praised. To refuse his application on that basis would do little more than prove Dumbledore an avatar of the stability-before-dynamic policy that the would-be teacher had so firmly condemned as a propagator of their society’s problems.

Albus could tell just by looking that even if the young man should not attain this position that it would do nothing to quieten his passion. (If not here at Hogwarts, through widening the children’s horizons’, then where, _how_ would he attempt to plant change?) It would do nothing to slow the momentum that Albert was gathering to wield for the sake of change. 

Now that Dumbledore understood this much, he had to decide what to do.

On the one hand, there was no doubt that the Moriarty family was dangerous to make an enemy of. They were idealistic, they were driven, they had a purpose. Pureblood politics and prejudice dominated their lives, yet not once had that stopped them from treating Louis as their equal. They had motive to want change.

In a lot of ways that made them more dangerous than Lucius Malfoy or even Bellatrix Lestrange, if for different reasons. (As, generally, being political enemies did not mean that you had to fear for your life. Albus almost chuckled at how low his standards had fallen.)

Additionally, if he gave the young man the position, it would keep him close. It would allow Albus to…watch…over. His development. As well as over the children he sought to teach.

William strived to do what was best, but so did Albus when he was young. They both thought they knew what was best.

Perhaps that was a reason he should accept him. Who better to see that a young genius didn’t slip than Albus. Wasn’t he also still a teacher?

(More than anything, Albus didn’t want to be the one who pushed another young genius off the road that kept them above the tumultuous river of their passion. _He_ did not want to be the one who did that to someone else.)

On the other hand, William was seventeen years old and as inexperienced in the trials of life as that age implied. For the sake of letting a young adult find his own footing, it would be right to send him off to experience the world. To let him commit himself to studying at a muggle university. To let him experiment with his own limits.

The other applicant, Septima Vector, was simply more qualified to give guidance to children, beginning with the simple fact that she was no longer a child herself. 

…that was what he would say if the applicant was anyone other than William James Moriarty.

“I can see that you have put a lot of thought into the state of our current educational system,” Dumbledore said thoughtfully. “Understand that if I find your ideals are interfering with the responsibility you have towards the students, I will not hesitate to replace you.”

The young man straightened, serious, yet neither surprised nor excited. “I would hope so.”

The professor nodded, not surprised by that kind of response at this point. “You are young. For that reason, I would like a demonstration that you can control a class of children.”

Professor William James Moriarty looked at him, as perfectly composed as he had been the entire time. “If you are interested, Professor, as part of the non-magical homeschooling program I have been participating in, there is an internship I must absolve before I am allowed to graduate it. As it so happens, I applied for an internship at a summer school, which is scheduled to begin in a week’s time.”

Albus had to blink. "Such organization is admirable,” he commented with a chuckle. “I will be there.”

(It was not until years later that Albus Dumbledore looked back and noticed how neatly, smoothly, you might even say _perfectly_ everything, even every detail in this job interview, played out from that point on. By then, however, it would be too late.)

**Notes for the Chapter:**

> Dumbledore: Everything went perf-  
> Sherlock: Liam's handiwork  
> Dumbledore:  
> Sherlock: Liam's handiwork. Did he talk you into selling your soul?  
> Dumbledore: The student's souls, actually


	4. the great detective

John Watson was referred to Baker Street 221B and its resident by an acquaintance, without any of the warnings that John, in hindsight, felt ought to be attached to the person of Sherlock Holmes.

Though respecting the man more than he could put into words, there was no denying that any space Sherlock inhabited was positively bursting with idiosyncrasies. Beginning with the aggressive shrilling of a violin in the middle of the night, over the _definitely_ illegal and dangerous science experiments scattered all through the apartment, to the fact that privacy was an alien concept to him, Sherlock Holmes was a man that few could tolerate at length.

No doubt, that was why the rent was so cheap. Mrs Hudson didn’t even have the grace to be apologetic.

(There was also the strange annoyance with owls, the almost automatic defense that phones were a brilliant invention when justifying his lack of care for mail, and his almost spiteful seeming delight at praising whatever new and useful invention hit the papers, but they were little things in the grand scheme of things, easily falling by the wayside.)

John, having had a rapid introduction to all things Sherlock on the very first day of their acquaintance via a murder that framed Sherlock of all things, knew he had no place to complain. He’d signed himself up for it, and, actually, did so with some excitement. 

No matter the challenges, there was just something incredibly inspiring about seeing Sherlock puzzle through cases that had the police stumped, about seeing an intellect so sharp nothing seemed to escape it. The feats that logic, observation, and knowledge could accomplish were astonishing, even more so when wielded with so much purpose and precision.

Which was why the revelation that not only magic was real but was something that existed on Sherlock’s radar somewhere between ‘permanent annoyance’ and ‘not worth attention’ hit John with all the force of a freight train.

“What do you _mean_ , magic is real??” he demanded in a low whisper that nonetheless was almost a screech. “You mean the murder was done so well done it seems like magic. _Right_?!”

Sherlock grunted crankily. “Oh, I _wish_.” Chewing on an unlit cigarette, he looked with narrowed eyes in the direction of the victim. His foot tapped a rhythm against the soft foliage at the edge of a small collection of trees, an expression of such profound agitation that it could not help but escape his control. “That, at least, would be interesting. There’s nothing interesting about this.” He made a low sound of disgust.

No matter how long John gaped at him incredulously, he didn’t say anything else, which, finally, drive the point home. “You’re actually serious? Oh my God, you’re serious. What do you _mean_ , magic exists?!” John hissed at him, suddenly hyperaware of the police crawling like ants all over the scene of the crime.

Sherlock pushed off from the tree trunk he had been leaning against. “Just what I said,” he said, tone just that side of irritable that told John if he kept pushing the point, the man would lose his temper. “Lestrade, I’m done here,” he grunted in passing to the inspector, then ignored the man’s questions and protests yelled after them. John struggled to keep up, the confusion in his head making him stumble over a few roots before they emerged on a trodden path at the outskirts of the outskirts of outskirts of London.

A woman and her dog had discovered the corpse on their morning walk, called the police, who called Sherlock in the afternoon. Now it was already dark out, almost too dark to see the path if it weren’t for London’s proximity having prevented true darkness from falling for decades now.

“Sherlock.” With gritted teeth, John drew on a well of patience that had never been tested as much as it was when Sherlock slumped into one of his moods. “Would you please explain, for those of us not possessing your intellect, what you mean with _magic_ killed the man.”

“I didn’t say magic killed the man,” Sherlock corrected with a huff. “I said he was killed with magic. There is a killer. That much even the police got from the footprints, remember.”

“Yeah. A woman’s footprints. At a distance. There was no sign of struggle,” John summarized. “It’s not even confirmed that those prints belong to the killer.”

“Oh, they do,” Sherlock confirmed. “It was an ambush, though. The victim, and I’m using this term loosely, John, was focused on watching this path. He didn’t notice the person who had in turn laid in wait to ambush him. A flick of a wand, and he pitched over forward. The end. The killer disapparated. Lestrade is not going to find anything, no matter how much he searches. Not even a cause of death.” 

‘Wand.’ John mouthed the word to himself, suspension of disbelief faltering now that Sherlock seriously included magic in his reasoning. He took the more reasonable route. “What does ‘disapparated’ mean?”

Sherlock grunted, finally igniting the cigarette he had been chewing on for the past hour. “Teleportation, basically. Instant relocation is one of the few things that magic has going for it, if you ask me.” A puff of smoke was exhaled into the night air. “Not impossible to track, mind, but once they identify the victim, no one is going to bother.”

John started. “You _know_ who that was?”

“If you check the wanted lists, you’ll know too,” Sherlock dismissed his surprise. “That man was called Fenrir Grayback. Information is going to say something about him being a pedophile and kidnapper and generally a dangerous man. Truth is, he was a werewolf whose life’s mission it was to ruin as many lives as he could, and yes, preferably children.”

Werewolf. Tentatively accepting that Sherlock was not, in fact, having him on, John clung to the pragmaticism that any doctor had to have and that military service really drilled home. “You’re not going to investigate?” he asked, somehow even more shocked by that than anything else this night had thrown at him. “You’re just going to get the killer get away?”

Stopping before they reached the most outlaying houses, Sherlock heaved a sigh. “Given that the victim was Fenrir Grayback, the law is going to turn a blind eye anyway. They hardly care about werewolves anyway, and he was a serial killer.” Grumbling, he patted himself down until he finally found what he was looking for, pulling out a wooden stick from his back pocket. With a practiced yet annoyed flick of his wrist, Sherlock cut the tip through the air and…John didn’t know how else to describe it. Something _burst_ from the tip, almost like a water from a hose only much bigger and…glowing. The thing landed on the ground a few feet away _. Landed on its own feet._

Sherlock took a drag from his cigarette. “Tell Mycroft Fenrir Grayback’s been killed. Killing curse. Lastrade is already on it. Give him this location.” The…thing turned on its heels and disappeared into thin air. Like a ghost or something. 

John didn’t know what to address first. “You can do magic. _You_. No, never mind that. What was that??”

“The wizarding best equivalent of a phone, only much more difficult and eye-catching to use.” Sherlock scoffed, flicking ash from the tip of his cigarette. The stick…the _wand_ , he carelessly shoved back into his pocket. “That fact that’s is mobile is the only thing that it has going for it. Though, give technology another ten years…”

John was trying to wrap his head around _Sherlock Holmes_ doing _magic_. And being _scathing_ about the whole idea of it.

...Somehow, as crazy as this night had turned out to be, that last thought made John smile. That thought made _sense_. “I guess magic isn’t very logical?” he put forth. 

Sherlock stared at him as if he was out of his mind. After a long moment, he pinched the bridge of his nose. “Let’s put it like this, John. If you put an elementary school kid and an adult wizard in the same room, locked the door and told them to get out, it would be the kid who’d think of checking the window. And I don’t want to talk about this anymore.”

John folded his arms behind his back, looking away to hide the way he was grinning. Magic vs Sherlock Holmes seemed to be a long drawn out grudge match. “What are we going to do now? How are you going to investigate when the culprit can…teleport?”

That was how John H. Watson learned about Obliviators and the fact that, technically speaking, the very fact that John knew that name was enough reason for them to pay him a visit. Like they did for the police. Who forgot there was a case and cleared the area so that the magical people could investigate. Fortunately for John, Sherlock preferred to have nothing to do with the so-called Wizarding world, which meant so long as he didn't draw attention to his knowledge, it wasn't a problem. And even if it should end up as one, the good impression John had left on Mycroft had already been enough to make the man arrange the paperwork for an exception for John. Technically speaking. John probably didn’t want to know the details. He was just glad he didn't have to pull a gun on people who wanted to erase his memories. 

Amusingly, despite his dislike, Sherlock nonetheless had quite a reputation with the magical police, and their relationship was, if possible, even more fraught than Sherlock and Gusson’s. While Sherlock was forced to resort to stick waving to find invisible evidence, only to stomp off in a snit once done, John amused himself with how he was going to put _this_ revelation into a novel. Maybe some tick with hallucination? If worst came to worst, he could just write a magic fanfiction AU of his own work… Would have to be a different penname, though…

Sherlock’s sour tone after hours of silence cut him out of his musings. “God, I hate it when he does this.”

John blinked, reorienting himself. By now, they were back in 221B, one of the poor magic policemen having been bullied into delivering box of files after files to the apartment so that Sherlock could go through them without needing to set foot into the magic police’s headquarters, which was apparently as allergic to Sherlock as he was to it.

“Excuse me?”

Sherlock threw himself back in his armchair, scowling at the one file in his hand like a sulky child. “Damn it.” After a moment, he offered the file to John. “This's our culprit.”

Barely allowing himself to blink at the moving profile picture, John focused on the fact that, all references to magic aside, police files were still police files (even if these ones were significantly less structured), designed to give a rundown about a person.

Jennifer Stone, in this case. On file because her little sister was infected by a werewolf a couple years ago, when the girl was seven. Miss Jennifer was the girl’s primary guardian. Orphaned, though a grandmother still lived. The young woman, barely twenty, has been a leading face of a werewolf rights movement since, and already earned a victory on the point of…conditional employment rights in muggle society. (There was so much to unpack in here, John didn’t know where to start. _Employment_ rights? Muggles??)

“Why is it her?” The young woman didn’t seem like a killer, neither from her picture nor from her file. But as engaged as she seemed, there had to be something damning for Sherlock to be able to determine her guilt just from a dry file. Glancing at Sherlock grumbling in his armchair, he prepared to be regaled with another stunning display of intellect.

“You can tell from the footprints that Grayback had not been there long before he was killed while there were two sets of imprints of the woman’s feet. One older, one made just about the same time as Grayback’s.” Sherlock started with a put-upon huff, though the chance to explain his reasoning at least seemed to have broken his sulk. “It went like this: Miss Stone knew where Grayback would appear and went to the same location early enough that her natural scent would have time to fade. She hid herself, likely transfiguring herself into an ivy or something, and waited.” Restlessly tapping the tips of his fingers against the armrest, Sherlock tiled his head at the ceiling, almost sounding bored now if it weren’t for the underlying note of frustration. “Grayback arrived, laying in wait to ambush the family with the twins that the witness mentioned that take that way as a long way to school. Instead, he was ambushed himself. It's difficult, but for someone practiced and skilled, it would take but a few seconds to transform herself back and to hit Greyback in the back with an Avada Kedavra. If she did it right, her scent would hardly have had the time to spread, never mind that Grayback would have been distracted by his own hunt. Deed done, she disapparated, leaving a body behind for a non-magical person to find, for them to call the police, who’d request my help long after the disapparation could be effectively tracked. Perfect crime done and over with.”

John opened and closed his mouth a few times. Once more valiantly ignoring the mention of magic in the argument, he focused instead on the logic. “But why her? She has a motive, I guess,” if John read the subtext about freaking werewolves right, “but couldn’t anyone have done what she did?”

“Her shoe size and body weight match the footprints,” replied Sherlock at once, voice sliding towards annoyed again for no reason that John could see. “Werewolves have sharp senses, especially someone like Grayback, so it’s obvious that someone wanting to ambush him would need to be very well versed in disguising body odors and the like. You can do that with transfiguration, but you need specific skill and knowledge to transfigure yourself, especially into an inanimate, organic matter so different from human physiology. Check her Hogwarts subjects. She’s passed Transfiguration and Herbology with excellent grades and is now working at St. Mungo’s herbology department. Only the best manage that, especially at her age. In all of Britain, there are probably only dozen or so people like her who could manage what needed to be done, fewer at the required speed, and none of them would have her motive.” Sherlock finished with a scoff.

John felt his brows ripple into a frown as he once more looked down at the file. “That evidence is circumstantial, though, Sherlock. It’s not enough to turn her in.”

The detective sighed. “Believe me, I know. She probably used a replacement wand to actually kill him too, which would have long since been disposed of by now. Nothing short of her own memory could provide the evidence. And Veritaserum – that’s a truth serum – is only used in the rarest cases. Even if I accused her, found enough circumstantial evidence to make the accusation stick, no one is going to okay Veritaserum for the sake of a werewolf in general and Grayback in particular. Like I said, people are going to be glad he’s gone.”

“So there is nothing you can do?” John inquired. 

Sherlock’s face was like stone, displeased and frustrated. “No. Just accusing her would undermine Miss Stone’s whole movement. And the people who would pay for _that_ are children and adults not even afforded the decency of basic respect. I can’t do that. If I have to let a murderer like her go for that, then I will. 'sides," he tracked on, "I already solved the puzzle." 

Sinking down into a chair of his own, John marvelled, troubled, “I guess circumstances like this also exist, where luck and cleverness make a perfect crime.” He turned the case over in his head. From the very beginning – “Wait. How did Miss Stone know where to find Grayback. If the man had been avoiding police and magic police both. Did she just happen to find out and took justice in her own hands –“ Sherlock’s face twitched. John paused. “Sherlock.”

A long moment of silence stretched where John stared at his friend and Sherlock avoided his eyes like a guilty pre-schooler before, with an agitated sigh, the detective gave in. He ran his hands over his face and messed up his hair. “She didn’t just ‘happen’ to find out. She was _told_. Just as she, an idealistic and inexperienced person, was told how to murder someone in a way that wouldn’t get her caught.”

There was something about the way Sherlock said that.

About the way he lingered between words as though he could not help but admire the web he noticed only too late. A particular combination of bitterness and something harder to name, something close to wonder, to _awe_ but even that was not quite it. Something that only one person managed to inspire, in this _exact_ tone, in _this exact combination_ , in _Sherlock_.

John’s jaw unhinged a moment later, once he managed to connect the dots. He spluttered, staring at Sherlock, whose head was bowed and buried in his hands, fingers clawed into his hair to wrestle with the thoughts taunting him. Tension was strung so tightly through every line of his body radiated off him, control fraught to the point where just one spark could set him off into reckless, self-destructive behaviour.

Only one person could drive Sherlock up the wall like this _without even being present_ , and it was not Mycroft.

“The Lord of Crime has magic?!” Jumping up, John started to pace, muttering to himself. “The person who can stage crime like a play has magic. Does he use magic for his crimes?! Is that why he is so good at erasing evidence? No, wait, of course he has magic, otherwise you’d have –“

“John!”

John jumped out of his skin at the sharp tone, freezing as he looked at Sherlock who was glaring at him with anger narrowed eyes.

“Don’t finish that thought,” he gritted out. “Just don’t. That guy relies on magic no more than I do. He isn’t that stupid.” It took him some visible effort, but Sherlock forced himself to control his ire. His gaze skirted away again. “If he were the type of person who needed magic to do what he does, I would have long since caught him." Another pause, lingering, charged with too many emotions to name radiating from Sherlock passed before the man admitted slowly, "He wouldn’t even be worth the _chase_.”

And there it was.

The biggest, truest vice of a man ruled by reason, a solid sense of justice, and love for mystery.

It scared John sometimes that he couldn’t tell how much Sherlock was willing to compromise for the sake of this hunt, this _hunger_ of his that nothing else ever seemed to be able to sate. John’d already glimpsed a hint of its depth when Sherlock had a gun on Hope, when the sheer intensity of that hunger had locked John in place, frightened by this unpredictable, wildness in a person he suddenly didn't know.

John suspected that until after he had pulled the trigger, Sherlock himself hadn't known if he would kill Hope. 

The desire of his scared Sherlock too, John thought, looking at him now. That shouldn’t be as relieving as it was.

“In the first place, magic isn’t what you think it is, John,” Sherlock continued, managing to calm down even more as his mood slid into more familiar territory of annoyance. With _magic_. And here his therapist told him that he should enjoy a quiet life! “People who don’t know that magic is real have these grandiose ideas about it. Told in fairy tales and fiction and all. They think that with a few words, maybe some rituals thrown in on the side, all problems can be solved. In truth, magic causes more problems than it solves.”

John sat back down, leaning with his elbows on his knees. His curiosity sparked as the sudden change in topic, though an explanation why Sherlock disdained something he was obviously well familiar with, and practiced, was probably long overdue. “How so?”

His reply was at first only a grunted sigh. Then, Sherlock pulled out his stick – a wand! – and…just flicked it through the air.

A pot set itself on the stove, the fridge opened for some sauce and water flew from the tap. In no time at all, there was a soup boiling and stirring itself.

“If you can cook something just by waving your wand, who is going to do it manually?” Sherlock posed rhetorically. “If all you need is a few words to cut vegetables and manage the heat, how are you going to learn how to safely wield a knife, how to regulate the temperature, _how to operate a stove_ –“ He cut himself off, exhaling forcefully. “The point is, John, that people always try to make things more convenient for themselves, and magic is so very convenient in all the little things in life that _an entire society_ is _incapable_ of using their _heads_ to solve _their own damn problems_.”

John was still staring at the kitchen. “…ah,” he said when he turned back to find Sherlock watching him. “That explains…pretty much everything.” For a left-brained individual like Sherlock, definitely. John still couldn't help thinking it was cool, though. Except for the mind-wiping bit. 

His comment startled something almost like a laugh out of Sherlock. “Doesn’t it just. God, I don’t want to talk about this anymore. It’s bad enough that that guy shoved another of these annoying gray-area cases in my direction. I hate it when he pulls my strings like this,” he finished with a grumble, shooting a foul look at Miss Stone’s file that John had put aside. “It’s like he’s rubbing in my face that he knows exactly what I’ll do. If he wants to test me, he should go about it seriously, like with the Hope case. And make it a good mystery. I know he's could have.”

That gave John a pause. “This was a test?”

Sherlock rolled his eyes. “Obviously. Why else let Grayback’s body be discovered? It would have been easy to dispose of before it was ever found. No, he set this case up just this way to see if my sense of justice and desire to get one over him would outweigh the social change the woman is spreading.”

“…so the Lord of Crime used Miss Stone? If you decided to accuse her, you could have ruined her important work, and still he set it up in a way that left you enough rope to catch her.” Not that John wanted to have sympathy with a murderer, no matter how understandable her actions, but he couldn’t help a sting of empathy at being at the mercy of someone with an intellect that could match Sherlock’s. It made him doubt how much of the responsibility should even go to her.

“’course he did. But you can tell he likes what Miss Stone is trying to do, that’s why even as he set her up as a test to feel me out, he gave her a safety net. At most, her movement would be set back by a few years. The identity of the victim and lack of conclusive evidence assured as much.” Again, there was _that note_ in his tone, the sort that made you think of savouring a Château Pétrus while at the same time regretting that each swallow taken would never return. 

John rubbed a hand over his face, suddenly tired. “You know, sometimes you sound like a jilted lover, Sherlock.”

Pause. “It's a game, John. Nothing more. It's exciting taking the webs he spins apart. You know that. It's just that he is the only one who can make them. That's the only thing that makes him special.”

**Notes for the Chapter:**

> John: Have you heard of this thing called 'awfully specific denial'?  
> Sherlock: Yeah?  
> John: I'm just saying  
> Sherlock, dead-eyed stare: Just saying what  
> John:  
> Sherlock:  
> John: Nevermind...  
> 
> 
> Sherlock, being a very logic-valuing, left-brained individual with a healthy appreciation for _reasonableness_ and common sense I could only make him a wizard if he did, in fact, disdain the fact that something as annoyingly violate and arbitrary as magic even existed. Even if he could use it himself. 
> 
> Fun fact: he and William both devoured muggle science of various topics on the side while at Hogwarts as a means to remain sane when surrounded by people who would not be able to make sense of a Venn diagram if it kicked them in the teeth. 
> 
> To illustrate how incredibly nonsensical and _frustrating_ wizarding England can be, I refer you to the best HP crossover ever, [snipers solve 99% of all problems](https://archiveofourown.org/works/20644262/chapters/49023794) . I cannot put it better than that fic does. No one can. For some people wizarding society is the best thing ever. To ratio-valuing people like William, Sherlock, and Edward Elric...not so much.


	5. modus operandi

“Hey, Liam! Good morning.” Sherlock grinned as he planted himself shamelessly next to William at the Slytherin table. Being somewhat known as eccentric didn’t stop filthy looks being shot in his direction for the presumption, and especially didn’t prevent the air filling with frost from combined animosity as Sherlock carelessly swept breakfast out of his way to lean on the table around William to get a better angle to observe his expression since William didn't turn to look at him. 

For that bit of cheekiness, he got the delight to watch William’s eyes widen slightly, part genuine, which meant Sherlock really caught him off guard today, but mostly neatly affected. Even though it was part of their game, Sherlock still found himself wishing the latter was only for the audience, but even if they were alone, William would not drop the act.

“Can we help you, Mr. Holmes?” An icy voice from William’s right cut into Sherlock’s thought like knives - like the metaphorical counterpart to the literal ones Louis looked like he wanted to put between Sherlock’s ribs.

In response, Sherlock shot the guy a lazy grin, earning himself a twitch of an eye, but as much fun as poking at Louis' temper could be, it was never him Sherlock’s focus was just… _drawn_ to. “ _You_ can’t, I’m just here for Liam. Tell me, what do you think?” The last part was of course directed at William, who's attention had drifted during that short exchange from Sherlock to his plate that Sherlock had moved out of his reach. At the question, though, ruby eyes slid towards him and Sherlock's grin widened even as he had to hide a shiver in response to the thrill William's attention always ignited in him. 

William finally put the knife and fork he had still been holding down, the simple motions slow and smooth to the effect of effortless elegance that half, nay all, of these other 'noble' born morons couldn’t match if they tried. The silver clinked before it vanished, summoned back to the kitchens. Only after he had laid his hands flat on the table and laced his fingers did he reply verbally. The look in his eyes was light yet unreadable. “Unfortunately, I cannot say that I have had the chance to read the paper yet, Mr. Holmes,” he said with good humour. Pointedly, he dropped his ruby gaze to the Prophet crumpled in Sherlock’s hands.

Sherlock smirked, leaning in closer, searching William’s gaze for a hint of calculation. (The icy aura from the side got stronger, but William did not even blink, which was what mattered to Sherlock.) “Come on, I bet you can guess what it says,” he murmured.

As always, though, William pulled back. (After just a hair of a moment too long that, as often as it was repeated, _could not_ just be Sherlock’s imagination, right?) (He _did_ have William’s attention like William had his, _right_?)

William rearranged his position on the bench so that there was a more appropriate distance between them, displaying just the right mix of soft politeness and resigned tolerance of Sherlock’s unstoppable antics.

And he smiled. Part of Sherlock’s brain wondered yet again if William practiced looking that perfect in the mirror. If it was a tactic to distract from his brilliance, Sherlock wouldn’t put it past him.

“Well, Mr. Holmes,” began William, eyes holding Sherlock’s again, and the moment just seemed to stretch in time with the slightly higher inching curve of William’s knowing smile, “if it is something that caught your attention to this degree, I can only presume that a matter of significant importance occurred. A scandal, perhaps. One of sociopolitical relevance.” Because they both knew very well that Sherlock wouldn’t give who-cheated-on-who news the time of the day if it was literally the last intellectual stimulus on earth. William made a show of thinking, a curled finger settling below his chin. “A murder, perhaps,” he guessed. Guessed! It was almost cute how William pretended to not be as sharp as he actually was only to seemingly by coincidence say exactly the right thing after all. Cute, see, because everyone _bought_ it. _Kept_ buying it. They were _so_ blind, and William playing with that pretence in front of Sherlock, who he knew didn't buy it, meant that this was William's version of being snide with the shameless eavesdroppers for being just _so blind_. Of course, they did not notice that William was rubbing their faces in something out of petty annoyance with their idiocy. No one did, except Sherlock. Not even William's brother, because this was a language William ever only spoke with Sherlock. 

Sherlock snorted on a delighted laugh, which quickly slid into a sharp grin that only William ever provoked. Game on. “Got it in one,” he confirmed. Surrendering to social norms for the sake of buying more William-time, Sherlock finally slid from the table to sit on the bench himself. The newspaper crinkled as he unfolded it on the table, revealing the bold headline _Family Found Dead In Ancestral Home._

While the headline may elicit sympathy, the moment the names of the victims were mentioned, the reception was bound to become a lot more controverse. Alecto and Amycus Carrow were notorious Death Eaters a little more than half a decade back, escaping Azkaban only due to alleged Imperius control and old money. 

“Who do you think did it?” Sherlock asked eagerly while William skimmed the article. His eyes flickered back and forth, golden lashes fluttering a miniscule bit when he made a connection the actual author of the text probably had no idea was there. Delight twisted in Sherlock’s belly, seeing this subtle display of insight that was so much _more_ than what even those who hailed William a genius could grasp.

“Interesting,” pronounced William eventually, and the tone carried so much meaning that Sherlock could not help but grin. That was the reply meant for Sherlock. What followed was empty words for the eavesdroppers. “The circumstances of the murders seem to by quite mysterious. There were signs of violence but not signs of forced entry in the wards. One would assume the murderer, or murderers, was someone the victims knew and would allow inside even in greater numbers. Yet the Carrows were not known to cultivate close friendships, the political ties of Mr. And Mrs Carrow aside.”

“I know who did it,” Sherlock told him smugly, and watched closely.

Something flickered in William’s eyes, a hint of _something_ , something that was real, and the smile he bestowed upon Sherlock a moment later was correspondingly stunning.

“That is quite impressive, Mr. Holmes. A feat beyond even the Auror’s Office. How did you manage it?” he enquired, tone cloyingly prompting.

Sherlock could no more deny him an explanation than he could stop the sun from rising. Didn't want to, anyway. “Yeah, well, the Aurors are all morons. All the hints are right here in the article, which is, you know, censored. No sensitive information for the public in an ongoing investigation, yeah?”

Willilam hummed, which was agreement even if others only heard a stock response. “That is true. I did wonder about that too.”

“Right? Like here, how they write there was no sign of forceful entry but plenty of evidence of struggle. Even their wands showed that they used combat spells before they died. The Unforgivable Ones included. Funny then that the late matriarch of the family as well as Alecto died from the killing curse.”

A moment passed in which they kept looking at each other, then gasps went up in earshot, what Sherlock was getting at obvious enough that even less bright listeners could put it together.

“Are you saying they killed each other?!”

“Watch your tongue, Holmes!”

“Are you crazy, why would –“

“Can’t you see that you’re bothering William –“

Annoyed, Sherlock silenced the peanut gallery with a distracted flick of his wand. Casting nonverbal was child’s play for him, had been for years, and nothing was ever quite as effective at reducing self-important socialites to fuming speechlessness as reminding them that, in fact, bloodstatus or no, Sherlock was better than all of them, without any effort, and there was _nothing_ they could do about it except being shown up if they tried.

(Sherlock was better than everyone, knew it, made no secret of it (unlike William, who was a great deal more discreet with how little school challenged him), and that might be half the reason he had no friends other than William, who would not admit to it. (The other half was that Sherlock was precariously short on tolerance for idiocy, and wizardkind as a whole was positively dripping with it.))

If glares could kill, Sherlock would be six feet under, but hey, if they could, Sherlock would not have survived Louis’ first year at Hogwarts, so.

William’s eyes glittered with dark amusement, which he hid by artfully lowering his lashes in thought. “An interesting theory,” he commented neutrally, as though nothing had happened, projected in such a precise way that to Sherlock it seemed accepting, even satisfied with what Sherlock did, while everyone else would only see someone who did not want to cause trouble by causing an argument with Sherlock. “How did you come about it?”

If Sherlock knew himself to be brilliant, and how to wield it to get what he wanted, William knew himself to be perfect in every which way, and how to use it for his purpose.

“Well, it’s obvious, isn’t it. Firstly, the article makes a note of how internally fraught the family was lately, mentioning how tragic it was that they were all killed when they were finally willingly under one roof again. Secondly, everyone knows, whether they admit it or not, that Alecto and Amycus had no problem using Unforgivables in the war. Thirdly, the house wards, which are extensive given the history of the family and the late Mr Carrow Snr's former position in the Ministry, are untouched. So, who could enter the grounds? Members of the family. Who had a motive? Well, if you loathe your sibling to the point that you’re willing to curse them at public events, experienced killers would not need much more. The signs of conflict? If you arrive to murder your sibling only to find that your sibling has the same idea, that could cause some damage. And a mother who was willing to pay her whole family inheritance to keep her children out of jail wouldn’t hesitate getting between them, now would she.” Sherlock smirked, watching William’s profile closely.

William met his gaze from the corner of his eyes, ruby eyes assessing. “There are quite a few assumptions you are making here, Mr. Holmes," he pointed out mildly. "I also feel obliged to remind you that an accusation of corruption in the body of judgement of our state is not something that should be made lightly.” Sherlock could all but feel the aggressive vindication radiate from the other members of the Slytherin house as they fully expected their own genius to defend the honor of a pair ex-Slytherin, blood purist murderers. Went to show what they knew. William had said _'_ should not be made _lightly'_. In no way did he say he disagreed. Which the way William paused, deliberately, drawing the moment out to let thoughts he planted sink into the oblivious little minds, only confirmed. 

Such a perfect, pretty, manipulating liar. Sherlock would feel pity for William’s hapless victims if he wasn’t too busy admiring the sheer _artistry_ of it all himself.

When William spoke again, Sherlock had to make himself focus on his words. “However, I do admit that your theory holds value worth investigating. I was a witness, you see, of the sibling’s fallout at the Christmas celebration. It was quite shocking, especially as I had only just conversed with Mr. Carrow a few moments earlier.” The little sad sigh he let out was entirely faked but the Slytherin audience ate it up, suddenly reconsidering their rigid stance of Slytherin solidarity since even their precious, faultless William James Moriarty was deeply shaken by the enmity between the siblings.

After letting the silence following his words linger for just long enough to let the message sink in again, William turned to his brother, unsilencing him, and only him, as though he wasn’t perfectly capable of undoing Sherlock’s spell in its entirety with about as much effort. “Louis, would you mind writing Albert of Mr. Holmes’ theory. If he passes the message on, the Auror’s Office should be able to prove or disprove it easily enough.” 

Ever the overprotective foot soldier, Louis shot Sherlock another glare that could curdle milk before rising from his seat. “Of course. Classes are starting soon, however, so may I _suggest_ that Mr. Holmes return to his table? It wouldn’t do to go hungry.”

Sherlock returned the look with a grin that was all teeth. The same overly formal politeness that was so aggravating from William was like water of a duck from Louis.“So thoughtful of you, Liam’s brother. But I’m not done talking with Liam yet.”

They glared at each other, sparks flying, while William lifted a hand to the lower half of his face to hide what had to be a smile for a tolerant moment, before something changed just-so (Sherlock's good mood pummelled - time's up) and he said to Sherlock appropriately apologetically, “Unfortunately, Mr. Holmes, I’m afraid that there is a matter I must discuss with Professor Snape before class. So, if you would excuse me…” He made to rise, cloak rustling and brushing against Sherlock’s knee as he swung a long leg over the bench.

“Really?” Sherlock said loudly, the familiar routine of William's retreat grating in a way that made his tone sound sharper than he meant it. “That’s a shame. And here I was, wanting to discuss the pureblood serial killings.” As one, the spellbound Slytherin table inhaled, shocked and alarmed, so a reaction like that in itself was nothing special. Yet the way Louis froze in his retreat, the way he went so dangerously still. The way William looked over his shoulder back at Sherlock, ruby eyes deep and endless. Sherlock looked back, head tilting with challenge. 

Neither reaction was anything as obvious as a tell. Of course not. Why would it?

Given William, it was well possible, they had already connected the dots themselves and were now just surprised that Sherlock called attention to the topic so crudely.

It could be that.

It could be that they were worried, given that they were a pureblood family themselves who had already lost half their family.

It could be anything.

But Sherlock had always been searching for a reason that truly, _deeply_ justified the way William molded himself so perfectly into a society and system that he despised. Flawlessly orchestrating the murder of elite members of this prejudiced and corrupt society in such a way that an ‘investigation’ didn’t even need to happen would be sufficient reason. It _could_ also be that _that_ caused the brothers’ focus to home in on him.

Sherlock’s blood raced with countless emotions, the chance of a real, true chase, with high stakes, one that only one of them could win threatening to set him alight. His stomach churned around its emptiness, but that sort of hunger was so easy to ignore it was almost laughable compared to the other one that seemed burrowed into his very bones. His heart hammered against his ribs as though it wanted to jump out.

It could be _anything_.

William’s eyes flickered away from him, contemplative. “Serial killings, you say. A concerning prospect, if true. However,” he swept his gaze over his housemates who now, with this, after already having been forced to swallow Sherlock’s presence, lost the last of their appetite, “hardly a discussion for breakfast, I think.” He smiled, an expression that was as pretty as it was deflective. “Perhaps at a later time.”

‘Perhaps at a later time’ was code for never, with William. After all, Sherlock always had to bug him into paying attention to him and even then, the time afforded to him was always limited. Like now.

Sherlock sighed, but his eyes kept burning into William’s. “Sure, later.”

This used to be purely fun, back when they were younger, when Sherlock was still childish enough to take enjoyment from the way he could just overwhelm whoever was granted William’s attention at the time to monopolize said focus all on himself. The other students had been less competition and more pieces that William moved that Sherlock had to sweep aside, William’s own brothers definitely included, which said brothers had known and accepted with with varying amounts of grace.

Nowadays, their back and forth was still fun - Sherlock was not easily deterred when something fascinated him - but the mixed signals were also at this point more confusing than amusing.

It would be simple, as the rest of the school evidently thought it was, if William really was only putting up with him, humouring him, tolerating him from the pedestal of a higher road. That would be a clear message that no, actually, William wasn’t at all interested in playing.

But then what was with the moments that stretched just a second too long? With the stock replies delivered in a cloying slow voice that William had to know rattled in Sherlock's head like a challenge for hours after. What about the too-clever looks from beneath thoughtfully lowered lashes?

To Sherlock, doubting himself was an event that happened once every blue moon. Lately, however, the blue moon appeared every day. Or rather, every day he interacted with William. (Which was pretty much daily because the Slytherin Perfect was still the most interesting thing in the school. In the country. In the world.) Second guessing his every step was an uncomfortable feeling. He didn’t know how the rest of the world did it.

They have gone to school together for six years now. Sherlock had insisted them to be friends for as long. Never once had William reciprocated, and their relationship had changed not even a little from the forms they negotiated in the first few hours of knowing each other. Problem was, they weren’t eleven-year-olds anymore. The rules made by children, no matter how brilliant, were still rules made by children.

In short, Sherlock didn’t know where he stood with William. And William never gave anything away, not even for this. For all that he knew, Sherlock could be just another piece on the board for William, not special in any way. (That thought tasted bitter, made something hollow stir in his blood in a way that was far too similar to the _hunger_ to trust.)

It was like traipsing in a darkness that not even the most powerful Lumos Maxima could brighten. Not all of Sherlock minded, he _did_ love the mystery, but a niggling, persistent, growing part _did_ , wanted nothing more than for William to look at him without those hundreds of layers between them. Sherlock wanted to _know_ him, not to guess him. That in itself didn’t even have to compromise the game so…

So, William either didn’t want the same, or…

Sherlock stared after him with narrowed eyes that someone people might just interpret as a glare, especially considering the colors of their uniforms. Even once William had left the Great Hall, Sherlock’s expression didn’t change, though he rose from the Slytherin table and blindly made his way back to Gryffindor’s, where he promptly ignored all attempts at conversation, so deeply lost in thought he was.

William either didn’t want the same, or…

**Notes for the Chapter:**

> William and Sherlock's relationship is complex, people. I didn't really get just _how_ complex until I wrote this.


	6. brotherhood

The pavilion was Goblin-made, not that there was much visible that could display as much. The walls were made of glass, the corners and fixtures spelled invisible so completely that at first look, the clearing in the middle of winterly barren gardens seemed to harbor no such quaint building at all. At second look, however, it became apparent that no matter how much the wind stirred bony branches, not a hair moved inside that area.

At a third look, the colorfully blossoming plants’ floral scent would prove that they were not merely artificial copies meant to create a permanent illusion of summer.

A delicate, silver ornate coffee table stood in the middle of the mosaic floor, a small collection of pastries prepared. Three matching chairs around the table were occupied. Though each of the young men had a plate in front of them, what truly drew their attention was the newspaper they had spread in the middle.

The youngest of the boys frowned at the headline and the photo of a collection of cold faced men and women. “If that man is truly gone, then he won’t be able to fill the role of villain,” he said, sounding like he did not know if he ought to be relieved or troubled by the consequences.

His elder brother reassured him. “That man was not suitable in the first place, Louis.” Fine golden hair swaying slightly with his motion, the boy cut a slice from a strawberry shortcake and lifted the creamy treat to his mouth. His actual attention was on the conversation, however, red eyes clever. “His vison too narrow, the methods he used too simplistic for our purposes. We need more tools than fear. Certainly, we would have been able to take advantage of the chaos he caused, but his death would have been one eventual step in the plan anyway, sooner rather than later. He caused suffering too deliberately.”

The eldest of the boys leaned back in his chair, a complex expression on his face. “It will have to be us after all, then,” he judged, and silence fell after those words, as if even the air could taste the ominous, grim weight of them though the tone with which they were delivered was measured and contemplative.

The middle child’s gaze flickered to him, then to the youngest, and back. Nothing of what he thought showed on his face. “That’s the way it looks at the moment, yes,” he replied in an identical tone, and did not belittle their resolve by apologizing for what fate _his_ plan would see them meet.

The eldest, Albert, polished off his plate, the sweet taste hardly registering as something special after a lifetime of being presented only the best. It was commodity to him, just as the silver fork was expected, just like china was the only acceptable tableware, while other people even in this very country did not have enough to eat for no reason other than arbitrary factors like luck of birth. Skin color. Race. It disgusted him, just as it disgusted his brothers.

The fact that they had met, that they could even call each other brother – _that_ was the true fortune, not what blood flowed through his veins. Speaking of his brothers, however...

“William made a friend,” Albert revealed to Louis with a grin, causing the youngest to blink in surprise as the words registered, fork stalling halfway to his mouth. “He is quite the character, I must admit,” the eldest continued. The sly, amused look he slid in the direction of the middle child was entirely brotherly in nature.

“A friend?” Louis repeated, expression remaining stuck between relief and scepticism. With some puzzlement, wondering if they were playing a joke on him, he glanced between his brothers. Were Louis anyone other than the precious little brother, William’s amiable expression would tell him nothing, but he was not, and thus his eyebrows shot up.

Albert made a confirming noise at the back of his throat. “I must admit, I never thought I’d ever see someone capable of rivalling William, but that boy does come close. It’s quite fascinating to observe,” he stated, thinking about the push-and-pull, back-and-forth, nothing-and-less-than-nothing interactions he had witnessed. There were few people their age (and quite a few adults) that William could not control as completely as a puppeteer their puppets with but half a glance, but that Gryffindor was definitely one of those few. “He isn’t exactly the type to be deterred either.”

Louis only heard the most earthshaking part. “ _Rivaling_ William?” he said with a sharply sucked in breath. “That’s –“ cutting himself off, he glanced between his brothers again, lingering for a moment longer on how William stirred his cup of tea with motions like clockwork, conspicuously unreadable. Louis bit his lip. “Isn’t that…dangerous?” he ventured in the end and William sighed, clicking his spoon against the rim of the cup.

“He was unexpected to me too,” he allowed. A moment of deliberation passed while he took a sip from the amber tea. “But don’t worry, Albert, Louis. If Sherlock Holmes continues to insist on involving himself, then there are several roles he may be able to fill. We’ll have to see when the time comes,” he assessed, thoughts turning inward to a horizon only he could see, countless possibilities considered in the span of a heartbeat. 

“I wasn’t worried,” assured Albert. “I trust your judgement, Will.” They were united in their purpose, no one more driven than William after all, and if William wanted to have a friend, then that was all there was to it. No matter how clever that friend, there was no reality in which William would allow him to become a risk. “I’m far more concerned about the current situation. The Dark Lord was useful in terms of polarization. With his sudden absence, society lost one of its driving forces.”

The newspaper spread between them thematised exactly that. Without Lord Voldemort exerting pressure on society from the one end, the Ministry, still in it’s momentum to _catch up_ no longer had a counterpoint, which garnered them ‘success’ after ‘success’ that they were unprepared to deal with, and thus dealt with sloppily.

“Indeed,” murmured William, staring at the faces on the frontpage with the distinct nuance of someone not truly seeing what they were looking at. “However, as unexpected as his disappearance was, I’m not sure he is truly dead.”

Neither of the brothers looked surprised by this assessment, having already taken the development of the recent months apart from a strategical position, which was something either no one else seemed to do or seemed to pay heed to.

William offered them his reasoning nonetheless, preferring after all to only hold as many cards as he had to close to his chest. “For all his faults, the man was a capable wizard,” he began with a low murmur. “The details, in as such as they are known to us, may be restricted, yet it is obvious that there are far too many inconsistencies. Lily and James Potter were found murdered, yet their son survived. There were no traces of spells or rituals that would explain their passing while the boy yet lived. There were no traces of the Dark Lord’s body either. The only actual basis for his presumed death his lack of recent presence and retaliation. But that could have countless reasons.” From the top of his head, William could think of a dozen reasons why _he_ might do such a thing as suddenly vanishing, though granted, Lord Voldemort’s tactics were far too different from his own to be in any way comparable. “The only reasonable explanation is that something unexpected must have occurred. Something that perhaps wounded him seriously. His movement is not one that he could lead while appearing weak, so he may have been forced to retreat for the time being. With the lack of body, the odds are significantly in favor of his survival.” With a mild tone, he surmised what the rest of wizarding Britain failed to grasp. “We’ll have to investigate that.”

“If he does plan to return to the stage, William _does_ need to know what role to give him,” mused Albert aloud, nodding. “I see, yes. Information truly is the foundation of every scene.”

William pressed his lips together, curling them in a warm yet cold imitation of a smile. It was, some would say, his murder plotting face. “ _If_ it is true, which we cannot confirm, that there was Avada Kedavra used on the boy, then that narrows our search parameters for what may have happened.” He lifted his gaze to the smartly dressed man standing half a dozen meters away at the entrance to the pavilion. “Do you have suggestions, Jack?”

The man, a butler, was an odd sight, some might think, in a household that had magic and slaves managing it. Yet for all that magic could do, there were as many things which it could not, up to and including chaperoning children, managing estate affairs, and maintain the spells that managed the house.

However, as such tedious work was not often to the taste of people who had more money than their earth had worms, it was not uncommon to employ men or women who would mange such things for them. It was quiet, monotonous work that was hardly given the credit it deserved, yet for an old man who had learned the true face of life on the fields of a senseless war, like Jack Rayfield, it was just the right sort of quiet work. Retirement work.

No one looked at him twice, which meant that his instincts did not automatically make him run through the ways of best eliminating the threat.

Or at least, no one had looked at him twice until three orphans had come to into the care of his employers, and the rest, as they say, is history.

“The most extensive libraries in the country are at Hogwarts and at the Ministry, Little Will. However, both have restricted sections that I cannot see means of gaining access to at this time,” he responded after a moment of deliberation.

“We do not need the most extensive ones, Jack,” William told him thoughtfully. “We need the darkest, perhaps obscure. We are looking for places where knowledge too dangerous and too controversial to be appraised would be kept.”

That made Albert sit up straighter. “Now that you mention it, Will. The old Moriarty mansion used to have a library with its own section of forbidden books. It was a point of prestige among the circles that mother and father preferred.” Of course, that library and all it contained was burned down now.

Jack inclined his head, following up on the point. “The Rockwell Manor contains a small library as well; however I am not aware of any compromising works.”

“It was blood-locked in my family’s case,” explained Albert. That was why William didn’t know about it yet after all, since scouring the library was one of the first things he had done to absorb all knowledge about this alien, Victorian-like society he had his brother had been drawn into. Albert had smuggled him books he was not technically even allowed to touch whenever he could but what he did not know existed he could not request to read. 

William nodded. “No doubt, that will be the case here as well. We’ll have to see what to do about that,” he said easily, as though they were not discussing breaking trust and drawing blood if necessary. Though, then again, what trust was there to be broken if the Rockwell’s had already tried to sell Louis out? “Once Albert and I must return to school, I will leave the research to you and Louis, Jack.”

“Of course, Little Will,” replied the butler immediately. “We will compile reports of all we find.” He was nothing if not efficient.

However, William cautioned, “Don’t expect too much. If it were a simple matter to discover, someone already would have.” The so-called ‘staple’ Dark Arts were the first the Aurors and Healer’s looked to to prepare themselves, after all.

“Perhaps we can arrange for visiting the libraries of other pureblood lines as well,” suggested Albert. “The Malfoys are under scrutiny, so they would be a matter for the future, and the Lestrange’s assets have been seized. However, the Black family escaped much backlash due to having publicly disowned their heir when he was still attending school. Then there’s the Macnairs. Crabbes. Goyles.” There was no end to the list, in fact.

“But I doubt we would be granted access to their forbidden books. We would have to gain their trust first,” pointed Louis out. Which of course had its own complications, one of the biggest being, “It would take time and the plan doesn’t see Albert expanding his influence in that direction.”

“True, Louis,” acknowledged William, watching as his brother moved his own plate away to better look at the newspaper. “However, there are ways around that that are easily accessible to us, thanks to Jack’s help. What we need before that, however, is knowledge, like Albert said.” He smirked, just slightly, in a way that would seem almost diabolical to those who did not know him. “Where and how, in this case.” Elegantly lifting his cup of tea, he took a sip. “People can always be made…amendable.”

“I’ll see if I can get the Rockwell’s to take me to some of their social gatherings. Would that do, William?” said Albert, sipping the last of his tea before setting the cup aside.

“I will try to go along as well,” Louis volunteered immediately, and at the reluctant looks he received from his brothers, added. “If they are busy being snide towards me, Albert will be freer to act unobserved.” They still did not look convinced. “It’s okay, I don’t mind.” His expression firmed. “If a family has children, I think I might be able to get them to say something to me sooner than they would to Albert. After all, if they consider me inferior, they won’t watch what they say around me in a way that they would around Albert, right?”

In the moment of silence that followed, William pressed his lips together, not disagreeing, before he sighed, conceding the point. “Be careful, however. If necessary, there are other ways we can get what we need.” Acting without normative moral restrictions left a lot of paths open in the possibilities that William calculated. Sullying themselves with things they despised and marking themselves hypocrites were expendable costs in the great scheme of things, after all.

That said, without being able to tell how significant a role the (unlikely) late dark wizard would play in the future, it was difficult to estimate how much effort should be devoted to this. “This is merely a preliminary investigation,” William reminded them. “We have more immediate concerns at this time.”

“You mean the Death Eater Trials,” said Louis, mouth thinning with displeasure.

“You can hardly call that trials,” murmured Albert, picking up the fork from his plate fork and spinning it between his fingers absently. Such a delicate instrument, used daily and casually for convenience, cutting meat and cream with an equally soft touch. In the right position, it would take no more than a flick of the wrist to kill with it. Same as a wand. And anyone was capable of it, unlike magic. All it would take was the will to end a life. Just like magic. “The rich families buy themselves lighter sentences. The old families get let off easy because of how integrated their affairs are in the Ministry. Those who deserve death ten times over get a life sentence instead because this society lacks the decisiveness to deal with them permanently.” The knife slid into a position not meant for food cutting in his hand. On his face, however, only a calm smile showed.

“’Hell is empty, and all the devils are here,’ huh,” muses William quietly to himself. “How very true it is, still.”

Albert’s eyebrow quirked, intrigued. “It’s a quote?”

“From Shakespeare’s _The Tempest_.”

“Hmm,” said Albert, blinking slowly. “I’ll have to read it some time.”

William smiles prettily, eyes crinkling pleased. A moment later, he grows serious and glances down at the newspaper spread between them again. “We will have to do something about that. Malfoy. Macnair. Carrow. Killing them will be a test of how effectively we will be able to stage our perfect crimes.”

“But isn’t it part of our plan that the public find out about us?” questioned Louis. “Us, James Moriarty, I mean.”

“Yes, but gradually,” explained William. “In the First Act, no one is to know there even was a crime. That will be our modus operandi for years.”

Louis pushed his glasses higher on the bridge of his nose. “I understand.”

“On the one hand, given the people in question, I anticipate that there will be plenty of clients,” continued William, thinking leisurely aloud. “On the other hand, it is not going to be easy getting in touch with them. Jack, you will be our main contact, if you are willing.”

“If you require it, then of course,” was the prompt reply from the at-attention position retained only the sake of possible curious eyes from the manor in the distance. “If I may, there is someone I would like to introduce to you. A…former student, of a sort, of mine.”

“Oh?” Albert’s brows lifted curiously. “If it’s at your suggestion, then of course we’d be glad to meet this person.” The other two boys nodded in unison, looking at Jack with curious expectation.

Jack inclined his head. “Though he is somewhat crude, I believe he may be of some use to Little Will’s plan.”

William smiled. “Tell me about him?”

Jack cleared his throat, and obliged. “Though we have not had contact for quite some years, recently he informed me regarding the matter that caused dissent between us that, after some reflection, my assessment about the meaningfulness of his profession was correct,” he said, paraphrasing the man’s blunt letter spelling _fuck you were right, fuck everything_ in as many words into something more appropriate for young years. “At this time, he is still employed as an Auror. However, I believe he intends to be discharged from duty as soon as he is out of the hospital. His name is Sebastian Moran.” Some sympathy crossed the man’s expression, visible only in a hard twitch of a lined corner of his mouth. “He lost his team in an attack in August.”

That little information already seemed to be enough for William, whose expression turned contemplative, tinted with sympathetic resignation. “I see,” he said. It was quite evident to him that the culprit(s) were among the recently acquitted Death Eaters.

“We are significantly limited in our mobility so long as we attend school,” Louis acknowledged a beat later, flicking a glance between his brothers. “Albert will only graduate in four years’ time and I will be attending next year as well.”

Nodding slowly at Louis, William met Jack’s eyes. “I should like to meet with Mr. Moran before we make any arrangements, but it would definitely be beneficial if we had another ally.”

The man dipped his head. “It will be arranged.”

(Two months later, recently hospital discharged, newly ex-Auror Sebastian Moran dies in a self-caused explosion. The Daily Prophet reports a tragic descend into alcoholic dependency before the incident. Only a charred body was left at the scene. There was no investigation.)

“The next point we need to address is that at this point we are lacking means of interacting with non-magical society, never mind spreading our web,” mused Albert aloud, a contemplating crease between his brows.

Unexpectedly, William grinned, and though the expression was as polished as everything about him, this one had an edge that could almost be called mischief. “I have an idea about that, Albert. I’d like to meet Mr. Moran before saying more, though.”

(Around the same time, a muggle by the same name purchases a mansion in Durham in the name of a certain Moriarty family, which, while unknown, seemed to be uncommonly rich. A recently dead man went about transforming the place into an operational base that no one would look twice at before going and doing as instructed by a certain old man. Which is to say he left his wand behind and prepared to absolve a several years long crash course in all things muggle and, more specifically, muggle survival. Bloody waste after all if you couldn’t protect your own life just because someone kicked the stick that was your only weapon out of your hand.)

(The war may be ‘over,’ but for Sebastian Moran, it had only just begun, and he would never fail again.) 

After blinking surprised, Albert shook his head with a smile. “Take your time. I’m looking forward to finding out.”

William’s smile widened a bit more, though he lowered his head as if trying to hide it in a reaction that anyone with eyes could see was just like Louis’ when moved. That people failed to comprehend that the brothers who shared hair color, near enough eye color, and plenty of habits were blood related, rather than the ones who claimed they were and shared nothing except that claim, was another example of just how _blind_ people were to what they saw compared to what they heard.

That was why to open their eyes, the Moriarty brothers could not choose the means. All the impact that ‘death’ carried was sorely needed.

William turned the final page in the newspaper and folded it neatly. “It is unfortunate that the holidays are over in two days. There is still much I would have liked to do.” Unsaid went that he wasn’t much pleased with six and a half years of schooling still being ahead of him either. As much as they needed a basic education in all things magic, for people like them who had other matters of greater importance awaiting their attention, homeschooling would have been much preferred. But that would have been truly too unusual. Becoming invisible was half the reason they did anything at this point.

Albert, though, chuckled. “I don’t know,” he said, sliding William a teasing look. “I’m not sure your friend would endure longer than a fortnight of being depraved of your presence.”

Not lifting his gaze, William stroked his fingers neatly along the final crease more times than necessary. “He would consider it another facet of the game. He sees riddles and puzzles and chases everywhere, see. It makes him quite predictable simply because he can not be bothered not to be.”

Something in his tone had Louis’ eyes sharpen. “Is that person a _bother_ to you? I thought he was your friend.”

Enjoying adding fuel to the fire, Albert informed Louis, “He’s the one that eternally long letter that William got was from.”

At that William looked up slightly. A peculiar smile curved his lips. “He is nothing that I can’t handle.”

Louis’ gaze slid to Albert, who shrugged leisurely in agreement. “As far as I can tell, he’s a little like an overexcited puppy who imprinted on Will; Occasionally irritating with the demands for attention but placated easily enough.” Louis strict frown of disapproval didn’t ease as such but did lose an edge.

Hearing such a description for what was to be one of the most brilliant mind of the age, William almost snorted, though he covered it up behind a chuckle, which for no other reason than to stay in practice, he turned elegant with a precise tilt of his head. “Regardless of Mr. Holmes, however, Hogwarts also offers a social milieu that we cannot afford to pass up on,” he reminded his brothers. “Children often know more than they think they do.”

Jack cleared his throat, drawing their attention. “While that is doubtlessly true, I fear I must remind you that Mrs. Rockwell requested that you accompany her to Diagon Alley in an hour, Little Al. There is only so long that a walk through the gardens can stall.”

The brothers exchanged looks. “Very well,” said William, perfectly composed, and though the differences were near invisible, those who knew William could tell that he would now no longer the person who enjoyed a free afternoon with his brothers. He slid from his chair, the other two rising with him. “It would indeed not do to keep her waiting.”

**Notes for the Chapter:**

> Louis (before meeting Sherlock) and Albert: Oh, that friend/pet  
> William:  
> Sherlock: not so bright, are you two  
> William: you only have yourself to blame, Mr. Holmes  
> Louis after meeting Sherlock, waving a knife threateningly: WHAT ARE YOU
> 
> Do three _young_ boys conceive a plan that deliberately leads to their death? Of course not, if they have another option. If they could have nudged a bit here, a bit there, killed some people and made Voldemort seem responsible, spread the rumors they needed to in the end set him up as the ultimate villain that some hero strikes down in an epic conflict that changes society, then they sure as hell would have done that. Unfortunately, Voldemort was not qualified for the role. He used fear as his tactic, and murder as his method of choice to enforce his values. He was not about change, he was not about unification, he was not about equality. He was about control, domination, and purging those he considered unclean _by blood_ which goes directly against the purpose of the Moriarty Plan. William, had Voldemort not vanished in Godrics Hollow, would have found a different role for Voldemort to fill. Voldemort would not have been enthused. William would not have cared and you better believe that he would have been able to manipulate even Voldemort to his end.
> 
> In front of audience, even if it is soon-to-be-murdered audience, Jack addresses the brothers with formal titles. In private, he goes for the nicknames. 
> 
> The Moriarty brothers being in the business of killing without a trace, Sebastian, one of their hitmen is being send to study all the creative ways muggles have tested that people can kill each other (for the sake of their own survival). Those methods include, but are not limited to CO poisoning, guns, and hand to hand combat. For example: Wizards, who have no clue about chemistry, would not be able to identify CO deaths. William is definitely aware of that, though, or is soon going to be.


	7. Witch Weekly's Most Charming Smile

**Notes for the Chapter:**

> Heads up, everyone. In this chapter, you can see the butterfly effect playing out.

Harry’s adventures today were already more than enough, thank you very much, even before he had the displeasure of running into Malfoy.

Frankly, had the other boy not called out to him, Harry would not even have noticed him in his relief to be safe on the proper Diagon Alley again. But there he was, standing just off of Florean Fortescue’ Ice Cream Palour, scone of something colorful in hand. “You don’t want to go in there,” he said, jerking his head at the Flourish and Blotts, which indeed was Harry’s destination.

Harry stared at him suspiciously. “I’m here with the Weasleys –“

Malfoy rolled his eyes. “Oh, I know. And they’re in there. If you really want to, please be my guest.” His head tilted slightly to look down at Harry even though they were actually the same size. A nasty smirk curled his lips. “On second thought, please do go. It’ll be…worth it.”

“Why?” Harry looked between the shop, which was conspicuously bursting at the seams now that Harry took time to notice, and Malfoy, and made a split second decision. “What’s going on in there?” he asked, approaching Malfoy a bit so that they wouldn’t shout over half the street and attract always unwanted attention. It wasn’t as though he couldn’t watch the shop for the Weasleys emerging if he wasted a few minutes on Malfoy.

“Not ‘what,’” corrected Malfoy primly. “’Who.’” And he sneered. Not at Harry, for once. Shockingly. Harry’s eyebrows rose.

“O-kay… Who, then?”

Though he had to have anticipated the question, when it came to answering, Malfoy pulled a face as though had bitten into a sour lemon. “You have no idea how lucky you are to not know that…creature.” He took a whole bit out of his sparkly ice cream, like he was trying to get rid of a bad taste. “Let me put it like this, Potter. You think my mother and I would do something as plebeian as eat ice cream in a public space when we could have our house elf prepare something even better at home, in privacy, where we aren’t surrounded by all these _people_.”

Harry blinked. What on earth was a house elf? “Your mother?”

“Yes, do keep up Potter. My mother. You think I came alone and am standing around here because I have nothing better to _do_?” The Slytherin boy raised an incredulous eyebrow at him.

Crossing his arms, Harry glared. “Excuse me for not caring what you do in your free time. What was I supposed to think when you’re in fact _standing here like you have nothing better to do_.” He made a show of looking around. “Alone.”

Malfoy pulled a disgusted face at him. “My mother is in there.” He gestured with his head at the ice cream parlor in a way that was leagues more respectful than his pointing out Flourish and Blotts. “I, however, am out here. Would _you_ like to sit in on your mother and your future Professor discussing your future grades? Because I don’t.”

“I wouldn’t know,” replied Harry, snide, “given that I don’t have a mother.”

“Oh, woe is me, how could I forget, that’s all the claim to fame you have.” Malfoy was nasty right back before switching back on track before Harry could gather the steam to shout. “Let me inform you, if you ever find yourself in a situation where your _parental unit_ insists on discussing a subject you have not even yet decided to take next year, then you’ll want to beat a hasty retreat. Not that I don’t know my way around Arithmancy, but only an idiot would set himself up to be assessed for _talent_ by the _greatest genius_ the subject in question has _ever_ seen.” He blinked, as if remembering something important. “Never mind, I forgot that you’re an idiot. Go straight ahead then.”

Stopping scouring the inside of the parlor for blond hair that matched Malfoy’s, Harry shot a glower at the Slytherin. “What _are_ you doing here, then if not for ice cream?”

Malfoy sniffed. “Well, we _had_ been intending to buy my schoolbooks today, but as you can see…” The expression on his face once more twisted like he smelled something unpleasant. “I would rather subject myself to a third degree about Arithmancy - not that I had to - than subject my mother to _that_.” His lips curled in a disgusted sneer. “ _Gilderoy Lockhart_.”

Harry was just about to ask who the hell that was supposed to be when a Flourish and Blotts let out a – a _squeal_. There was no other word for it. The crowd of witches inside, leaking even onto the street, pulsed and tittered.

Without noticing, Harry had taken a good few steps away, wary and creeped out like he’d just seen Aunt Marge sipping tea from a cup she’d just fed her disgusting little dog baby creatures from.

Malfoy, in comparison, was unfazed, taking a lick from his crone. “You see,” he said. “Aren’t you grateful now, Potter, that you aren’t in there.”

Dumbly, Harry nodded. Ron and the others were in there? Maybe he should buy himself an ice cream as well and claim he didn’t know where they were…?

Malfoy sighed. Dramatically. “I fear to think what it means that we need that guy’s books for Defense.”

Harry had nothing to say to that. He still didn’t have anything more than a name and a very alarming reaction of an entire store. “So you _are_ killing time,” smirked Harry. “I knew it.”

Malfoy shot him a foul look before sniffing haughtily. “Mother and I are avoiding an unwanted experience, which is common sense for those of us with self-preservation instinct, Mr. Gryffindor. It is not just merely ‘killing time.’”

Harry shrugged, casually leaning against the wall beside Malfoy and keeping his eyes on the bookstore. “Sounds the same to me, but what do I know.”

“Precisely.”

They passed the silence (that Harry refused to acknowledge as comfortable, not with a Slytherin git) eyeing the store with mirroring scepticism. Rather than abating, the crowd of excitable witches only grew. Occasionally, a truly disgusting wistful sigh went up from them. Harry kind of feared for Ron and the twins. Were they alright in there?

Eventually, a woman with pale hair emerged from Florean’s. She looked so much like Malfoy, down to the haughty expression, there was no doubt of her identity. She was accompanied by a young man dressed in equally fine wizarding robes. At first, Harry wondered if Malfoy had a brother or uncle, but at second look, except for the base coloring – pale skin, light hair – they looked nothing alike. The stranger’s hair for example was closer to gold than the Malfoy’s almost silver, and the eyes –

The last time Harry had seen red eyes, they had grown on the back of his teacher’s head. Alarm made him straighten, his hands fall to his side, but when their eyes met, there was not even a hint at a twinge from Harry’s scar, which was so disconcerting that suddenly, the ruby eyes looked nothing at all any more like Voldemort’s.

Especially when the man smiled mildly. “Mr. Malfoy, Mr. Potter. Mrs. Malfoy,” he dipped his head at Malfoy’s mother, “thank you for your company, but I’m afraid I have an appointment to keep even if it seems that the other party is still quite occupied.” He slid a nothing-revealing look towards Flourish and Blotts. “It would not do to deprive the man of the hour of his well-earned triumph, after all.” Malfoy’s mother’s expression twisted into more profound disdain, at which the Professor smiled understandingly, a knowing glint in his eyes. Excusing himself, he approached the bookstore without fear, and Harry had to admit to gaping a little at how the women parted around him, kind of how he imagined the sea to have parted before Moses.

“A clever man,” Malfoy’s mother mused aloud. “Do pay attention to him at school, Draco, and you _will_ be taking his class. There is nothing quite so valuable as walking into the enemy’s trap, playing his game, and still walking away the winner.”

“Yes, Mother,” replied Malfoy obediently, barely refraining from a sigh.

The woman nodded imperiously, acknowledged Harry with a “Mr. Potter” and swept away into the street, Malfoy following on her heels. Harry only heard a “But Mother, what about my books –“ before they were swallowed, leaving Harry alone with his fatal curiosity that saw him not a minute later approaching the bookstore after all to overhear the witches gossip and trying to glimpse a look inside.

He would come to regret it.

The way Professor Moriarty braved that utter peacock of a man nothing sort of admirable, though. He was perfectly polite and admirable the whole time, even as Lockhart kept accidentally mentioning that he’d…unseated the Professor and his brothers from their long-held position at the top of the Witch Weekly’s most charming smiles…? The way Professor Moriarty congratulated Lockhart sounded sincere to the point that Harry almost snorted because this was about a _ranking of smiles_ what was so great about that??? But Lockhart’s prancing only intensified, eating it up. Which kind of was exactly what Mrs. Malfoy had meant, wasn’t it? The unchanging, unflappable smile curling the Arithmancy Professor’s lips seemed to say as much.

(No matter how much Lockhart pranced about and tried to monopolize the attention, his aura, his _charisma_ simply paled compared to the man he presented himself as triumphant over, who did nothing but stand in the background, obediently defeated, and smiling like a drawn painting, hands resting on his crane in front of him.)

**Notes for the Chapter:**

> Can you guess what brought on the changes?


	8. sorting

At eleven, Albert was young (though did not feel like it), angry (hiding it), and so dissatisfied with everything he saw that it hollowed him out.

The Sorting Hat was another of these things that made him question _why?_ without ever getting an answer. How was it right to categorise children for the rest of their lives with judgement made in but a sparse few moments?

Even Albert acknowledged to himself that his general upset with the Sorting was just a drop in the bucket, a target to direct his anger at with the excuse of righteous judgement. Below the empty feeling of purposelessness, he was even cynically upset with his own hypocrisy for judging like this.

But he was eleven and frustrated anew again and again every second he caught another hypocrisy so deeply embedded in their society that no one even batted an eye anymore. He did not yet know anything of protecting his mind, did not yet have a reason to, so the hat barely needed to touch his head before it already shouted –

“Gryffindor!”

It was the first real smile of his week that his Sorting was the greatest upset of stigmatized expectation since Sirius Black.

* * *

In Sherlock’s opinion, the whole Sorting thing was overvalued. He was biased, knew it, and couldn’t be bothered to do anything about it.

Sorting meant standing in a queue, meant standing still, meant _slowing down_ , and he was so very bad at that. His mind moved so fast, the rest of the world already seemed to get about doing its business at the pace of a slug even when he wasn’t forced to stand still to watch. Boredom was his nemesis, and one he was well familiar with at this age.

‘Private school’ had been correspondingly unwelcome a prospect. He had anticipated gritting his teeth, being jittery, and possibly already getting in trouble on his first day for ‘running his mouth’ in a way that his brother would have lectured him for with familiar exasperation. (Hey, it was not Sherlock’s fault that Random Person A didn’t notice Random Person B eyeing them up like a dog fresh meat. Or something like that.) And seven years of that, with a limited subject pool? Yeah, no thanks, Sherlock would have preferred homeschooling.

Granted, that was his position before William James Moriarty.

Just by meeting him, nothing was as expected. The mind-numbing boredom he had anticipated standing here, Sherlock could instead fill with gathering what knowledge he could about the other boy.

His name, for example.

William had not offered it on his own, a display of a surprising sense of mischief; Sherlock had put it together via the boy’s brother at the Gryffindor table, general knowledge, and seeing him react to the name ‘William’ being used by another student. Moriarty Fire, three siblings - and as little attention as Sherlock wanted to pay, it was a matter of survival at the moment to stay one step ahead, so he remembered the article from about a year back and the names mentioned in it.

William was not unaware of this scrutiny, but did not deign to acknowledge it beyond a knowing quirk of his smile. A challenge, in short. For Sherlock to figure things out while William refused to give him anything. Sherlock was definitely up for it, only a tiny percentage (which was still more than most people even had) of his brain following the ceremony.

(Though they did not speak, this moment would come to perfectly represent their relationship – Sherlock’s life being less boring because William was in it, and William always just a little _out of reach_.)

Him being sorted into “GRYFFINDOR” was an afterthought.

* * *

When the Sorting Hat was placed on William's head, he kept his mind deliberately calm and blank. It was not easy for him, one of the few skills in life that did not come to him naturally. His mind always ran far ahead, noticing things other people didn’t, and fitting those pieces into a bigger picture that told him all he needed to know about anything, but he could not allow that here.

The hat was purposefully made to intrude upon the sanctuary of his mind, to glimpse what William had never thought anyone could before he first heard the term ‘Legilimency,’ and though he was only eleven years old, there were secrets tugged away in his head that he would take to the grave. 

_Occlumency_ , murmured a voice in his ear nonetheless. _Impressive. Very impressive_ , _Mr. Moriarty. You need not fear, though. I am enchanted to be unable to reveal what I see to anyone._

_Nonetheless_ , William replied politely, focusing only on shaping those words and letting none of the half-shaped thoughts of loopholes of that phrasing and available counter-spells around the restriction gain traction in his mind. _There are memories I wish to share with no one._ Truth. The best lies always were.

_Hmmm. Well you don’t need to fear that. I am not capable of visiting memories as such. You seem already well versed in mind magic, so I’m sure you understand when I say that would be far too complicated._

William allowed himself to relax a smidgeon. When he had first heard about the Sorting Hat, he had his suspicions about how it could work, that was true, but the confirmation was appreciated. So long as the hat’s task was only to sense a child’s dominant personality traits, making it capable of viewing highly subjective and emotional memories would be counterproductive. No, despite what myths were said about it, practicality dictated that it was capable only of the most superficial, broad-scale intrusions.

Cautiously, William loosened his tight control on his every thought –

“SLYTHERIN!”

Well.

That was about as expected, though he did not need to be who he was to sense the searing stare of disappointment from the boy who was such anomality that he should not even exist. As he walked to the Slytherin table, he did not glance in the direction of red and gold even once, not even to meet his brother’s eyes, and told himself that the disappointment he felt himself was a profound sense of relief instead.

(Night-blue eyes that flashed like a fire-coated knife, that _saw_ , that _grasped_ , that _understood_. That left William for the first time in his life not pulling all the strings because someone on the other end pulled back. There was a promise on the horizon if he allowed himself to follow that threat, something rare and precious and one-of-a-kind, and curiosity niggled at him insistently urging him to find out more. However, such a flight of fancy had no place in the plan William lived his life for. No, Slytherin was for the best.)

* * *

To Louis the Sorting was mainly an obligatory event that he prepared himself for as if for war.

Though William assured him that even if he could not shield his mind perfectly, the hat would apparently not be able to peek at memories that contained far too much dangerous knowledge, Louis intended to be the one in control of his own Sorting. After all, not being a Legilimens who would notice intrusions, he had to assure by other means that he would not become a liability to William’s plan. At any time of the day. At any age. Being eleven was no guarantee for protection.

He stood among his future classmates with clenched fists and gritted teeth, though his expression remained even and impassive. A red-haired boy tried to make small talk with him, but he did not notice. The glare of his rust-red eyes could have ignited the hat.

When his name was called, he focused only on one thing.

_Slytherin_.

Slytherin. 

**Slytherin**.

Slytherin.

_Alright, I got it, no need to shout_. “SLYTHERIN!”

It was like a boulder falling form his shoulders and Louis wasted no time tearing the hat from his head (though careful to maintain to composure and dignity) and joining his brother at the silver and green table.

William scooted over, smiling with a genuine shine of happiness in his eyes, and that was well worth the cold looks he was subjected to from those who had not yet forgotten that the Moriarty House did not always have three sons.

The two of them looked over at Albert between the Gryffindors, who grinned back at them, hint of a smirk in the way it was slanted just slightly, and nodded. Everything as planned.

When Louis broke eye-contact with Albert, turning to speak to William, he found William however still looking at the other table, a little further down. Following the line of sight, Louis saw for the first time in person the one who would test his patience and discipline like no other.

Sherlock Holmes, did not look back at him, however, not once, not even for a second. Not so long as William was still holding his gaze. The moment that stopped and dark eyes moved on to him, Louis felt even from half the hall away as exposed as a bug under a magnifying glass. That was when he realized: William keeping Sherlock’s attention on himself was always also protection for the rest of them.

Sherlock Holmes was _dangerous_ and being ready for war was not at all being overprepared anymore.

**Notes for the Chapter:**

> So, houses: 
> 
> William was a shoe in for Slytherin because, well, his entire modus operandi is the very definition of slyness just as the very fact that he even conceived hi plan marks him as hella ambitious. 
> 
> Louis followed him there because he wanted to and the hat respects that. Not to say he doesn't have Slytherin qualities. On the contrary! For him it was always the choice between Slytherin and Hufflepuff. On the one hand he is hardworking, loyal, and incredibly dedicated to William and his cause. On the other, he _is_ William's brother by blood and his accomplice before everything even began. He knows how to be subtle, how to be _dangerous_ without being loud about it, which is very Slytherin of him. 
> 
> Sherlock is a Gryffindor because what else? He has no ambition to speak of beyond solving puzzles for, mostly, his own entertainment, which doesn't exactly make him a natural hard worker. He certainly has the smarts for Ravenclaw but it is never just knowledge for knowledge's sake with him. Gryffindor on the other hand, well ^^ Impulsiveness: check. Recklessness: check. Chivalry: Sure. ~~Determination~~ Obsessive tenacity: have you met the man?
> 
> Albert: Keeping in mind that he would have been sorted before meeting William and Louis, I figured that constant disgust and teeth-gritting at the injustice of society, as well as the determination to do something about it (even if he did not yet know how) would have made him fit Gryffindor best. Post William, he would have been Slytherin, though.
> 
> In countless crossovers, the Sorting Hat is always depicted as alarmingly competent at searching through memories and mindscapes and whatever. Not that I don't understand the urge, but thinking about its role in Harry Potter and considering how quickly it can be done sometimes, it's very implausible that it could search through real memories. If you experience something from the pov of someone else, how are you supposed to judge their actions? Viewing memories would make the Sorting Hat's judgement the height of subjectivity - it would sort the children as according to _how the children saw themselves_ and that is obviously what it's supposed to do. If it were, there would be no need for a Sorting Hat in the first place - you could just ask the children themselves which house they'd like.


	9. the elf

When Albert was a few months short of his seventeenth birthday, Mr Rockwell took him to arrange all matters required of a young heir of an old bloodline so that when Albert reached the age of majority, the man could bid him the best for his adult life without guilt.

Included in those matters was acquiring new service staff for the house Albert would buy. In other words, Mr Rockwell took him to buy a house elf.

House elves were sold not in stores like owls and cats, not even wizarding double standards would lend themselves to that, but at a bi-monthly auction. Due to how comparatively low the demand for new elves is in each country was, the auction wandered inside Europe from city to city.

This time, it took place in London and Albert almost choked on the irony of the country still internationally infamous for the ‘triangular trade’ hosting the modern, magical version of it behind closed doors while the organizers bathed in prestige.

What was different between then and now? What was different between human trade and elf trade? How could any of these people look in the mirror and not be repulsed by what they saw?

For all that magic was praised as superior, for all that the thought that non-magical people were simplistic, even barbaric was still firmly imprinted in magical society, it was the non-magical people who had outlawed slave trade and the magical ones who still practiced it with the excuse of convenience and flowing coins.

Albert kept his face arranged into a mild, attentive mien even as his stomach rolled with disgust and inarticulable fury.

“Unfortunately, the selection varies between seasons and depends greatly on outside events,” Mr Rockwell departed on him. “Healthy adults are the most useful and uncomplicated, however also rarely available as they tend to be firmly attached to their households. Only in the rare cases where a family dies out might a good example find its way to the auction.”

The auction was arranged to take place in an auditorium, the elves to be elevated and presented to be gaffed at and bid on. Albert unclenched his jaw. “I would think young elves to be more sought after,” he said. “As they grow to fill specific needs.”

Rockwell inclined his head. They were walking behind the stage where the preparations were being made and where potential customers had the option of viewing the ‘merchandise’ up close before the biding started.

House elves were so indoctrinated into slavery that they didn’t even need to be chained, like the slaves on pictures of past centuries were. He wondered bitterly if that paper-thin excuse was all the justification that society needed.

“While that is true, young ones still require special treatment. You need to be careful with them. They need to be taught the very basics of caring for a house. When you have another to teach them, then that is acceptable, however in your case…”

“Jilly and Finny passed along with my parents,” sighed Albert understandingly. To ensure that no one knew about William’s background, it had been necessary, and Albert did not care enough about the late elves to even say it was ‘unfortunate.’ They had been quite unpleasant all around. “I understand. And the disadvantages of an elderly elf…?”

“While they are experienced, that hardly outweighs the troubles that arise from their habits and time they need to adapt to new masters,” Albert's portly guardian explained. “Often, they are also quite distressed at being sold.” He nodded towards an elderly elf slumped on the floor with an aura of profound despair around her. Though she was weeping her eyes out and dabbing at the tears with her dirty tunic and worn hands, she did not move away from the shield in front of her indicating her starting price. “On that account, the younger, the more adaptable they are.”

“Quite like humans,” said Albert neutrally, and even though Rockwell acknowledged “yes, quite,” the man failed to show any indication of discomfort with the notion. Albert suspected that if it were non-magical people in the elves' place here, he would have said much the same. Repulsive. “I will take care with my choice, then.”

Rockwell smiled approvingly. “I offer you my wisdom, of course, as do the auctioneers. If you want to know something specific about an elf, they will be able to help you out.”

Obviously. Though Albert didn’t intend to trust a word of people who made profit with other beings' lives.

This façade of civilized culture was a prime example for how deeply _broken_ this society was.

The Moriarty family was not the only one in need of a new elf, though, and the clientele was from all over Europe. As they strode on, Albert caught snatches of other languages, of harsher cadences, and wondered with a distanced but no less clawing sort of despair if England’s attitude towards slavery was a Europa, or even world-wide phenomenon _._

_The world must change_.

_And it starts with England._

Albert and his brothers would use their lives, as well as the lives of anyone who decided to join them, to see to it.

_The world would change._

_If necessary, by fire._

(Sometimes, disgust with the state of thing made him wish razing everything to the ground was Plan A instead of one of countless alternatives. Surely, whatever rose from the ashes could only be better than _this_.)

Feigning moderate interest, Albert let his gaze jump from elf to elf. Truthfully, he did not want to buy one. More accurately, they did not need one. Even more specifically, they would not _keep_ one either.

Murderers though they already were, there were some principles that _could not_ be compromised.

Not to mention that someone with unlimited access to the house not loyal to the plan was too much of a security risk after all.

Propriety and status demanded that he bow on this matter to his guardian, however, which was why Albert was reluctantly here in the first place.

As those thoughts ran through his mind, his absent gaze fell on _him_.

There was no specific reason he should have noticed him. Out of the hundreds of elves lined up left and right, there was nothing that set him noticeably apart. Though on the younger side, he was not among the youngest here. He was quiet. Smaller than others. But again, not the smallest here. Unlike others, he didn’t make a fuss.

If anything, he faded so smoothly into the background to the point that Albert’s gaze _should_ have skipped right over him.

Albert stopped in place, looked again, and made his decision.

“Good day,” he greeted once he’d approached the elf, who only after Albert spoke, and after a reluctant pause, lifted his head enough to look up at him.

How interesting, Albert thought. Unlike the other elves who avoided eye contact as a form of respect and were skittish when they were obliged to break away from that, this one was… _exceptionally_ calm even as he tipped his head back and met Albert’s gaze with big, dandelion yellow eyes. Calm was perhaps not quite the right word. Blank, rather. Seeing and not seeing. A mental trick to distance yourself from what was happening around you. “What is your name?”

The elf lowered his gaze. Not because it was more comfortable for him, but because it was expected of him do so. “Freddy.”

“Freddy.” Albert repeated. “It’s nice to meet you. My name is Albert James Moriarty. You may look at me when you speak, if that is what you would prefer.”

Pause. Albert could feel the elf's guard rise, could feel the scrutiny. 

Then, without showing any visible reaction, the elf still looked back up. “How can this one help the potential Master?”

Firmly ignoring that, Albert smiled slightly. “As my family will be moving into a new house, we are looking for a house elf who may suit our needs.”

The elf said nothing in reply, did not try to praise himself or try to convince Albert that he was the best one for the job in his desperation to find a master.

“However, we are a somewhat peculiar family,” he continued, and lowered his voice so that the neighbouring elves would not overhear and panic, “tell me, Freddy. What is your opinion on clothes?”

The elf stared, and blinked once. “Clothes must be kept clean for the masters.”

Albert smiled, letting something genuine slip into the curve of his mouth and the look in his eyes. “Clothes for you, I meant.”

Finding a house elf not panicking at the very prospect was almost as surprising as waking up one morning and finding that the darkest wizard of the age managed to destroy himself. Wisely, the elf took time to deliberate a reply. “Such things are at the masters’ discretion.”

“But they should not be,” responded Albert immediately, and was rewarded with a slow blink of dull surprise. Albert changed tracks, aware that time for private conversation was running out. “Tell me about yourself. Who were your old masters? Do you have family?”

In the end, Albert managed to get quite satisfying answers before Rockwell arrived with an auctioneer, who was all too happy to give a resume for Freddy that sounded quite different from the story the background that the elf himself provided and that Albert gathered from what he left out. According to the official story, Freddy had been on sale for years now, always overlooked because he could just not seem to keep a buyer’s interest.

In Albert’s eyes, the young elf had managed to _make_ himself be overlooked. He did not want a master, he did not want what for other elves was their purpose in life - work, and he possibly didn’t care all that much about living and or this world.

To achieve what he did took cleverness, skill at observation, and a firm grasp on human behavior. And wasn’t that interesting.

For the sake of assuring Rockwell that he was making his decision carefully, he continued looking at other elves (feeling the attention of the only exceptional one here on him until Albert left his sight) until the auction began. Pro forma, he offered small biddings on other elves, but his decision had already been made when he found a soul that reminded him far too much of himself before he had met William. He had never been able to choose apathy, but at times, he had been tempted, if only it could release him from the never-ending disgust he felt with the world.

How very interesting.

Curious to see what would come from it, Albert could not wait to introduce Freddy to William.

.

Two month later, in the new Moriarty mansion near London, one Fred Pollock found part-time employment. A house elf was nowhere in sight. Meanwhile, one Sebastian Moran was from then on often accompanied by a pale, taciturn boy who slipped through crowds (and all sorts of security) as unseen and unremembered as a breeze in the wind. 

**Notes for the Chapter:**

> So. House elves. Slaves. Where do you get your convenient, unpaid housekeeper? Ask the neighbour if they'd be so kind to part with the kiddy!elves? I think not. In other words, _some form_ of trade with them had to be going on. Which, no matter how you twist it, means slave market! Yay! By the oh-so-civilized Wizarding World! Yay! My, if that's legal, what's going on on wizarding black markets. ~~James Moriarty~~ Enquiring minds would like to know.


	10. genius is a curse

**Notes for the Chapter:**

> Chapter 53: SHERLIAM FEELS, BIG BRO ALBERT FEELS  
> Me: Let's write!  
> My brain: so, about Mycroft

When Mycroft was young, his father said to him once “the world is empty.”

To young Mycroft, who had struggled with the world being _too full_ , his father’s rare words had made no sense. There was something everywhere, so many details to process, so much knowledge, so much so _painfully obvious_ , all happening _at the same time_ that Mycroft more often than not felt like a cup of water under a tap running at full power. It was so awful that even at ten, fifteen, or thereabout he had been able to understand the bleakness of his father’s tone. It was just the words, just the origin of that sentiment that he could not agree with.

When a few years later, his father was dead by his own hand and Mycroft stood with mother and brother before a lonely grave, he saw for the first time the future crystal clear, laid out like a painting with the finest strokes.

The future's path forked where he stood, one ending with a rope in a tree at the end of a barren, desolate path. Like father, like son. Like their whole family tree of short lives and madness.

The other was a path so cluttered with big and little things that the earth trodden path was invisible and had to instead be paved over the obstacles towards a goal that would draw him towards it like gravity. There was no end to that path, except time.

_That_ was the way that would make a too full world only full enough to keep him occupied without shoving him into monochrome hollowness.

Mycroft learned from his father’s life and reflected upon his mistakes. Though he doubted he was the first to try and starve off insanity, he had no living relatives from that side of the family tree to consult with, and the journals he studied revealed nothing but the same almost-sickness of their minds tracing back for generations. Which Mycroft had already known.

In any case, it was his life, and he could only give it his best shot at living it like his mother would like him to.

He spent some time reflecting and soul-searching, questioning himself on what he valued, what he wanted, and what he needed, and it was through this method that he started to formulate a plan. (One that was both alike and unlike the one a little orphan would develop decades later.)

Mycroft’s patriotism was a matter of survival. His strive to do better by the nation was not for the people’s sake. His desire to keep it running was a challenge he posed to himself. A fixation. ~~An obsession.~~ Something that could give him direction and purpose while being immaterial enough to last a lifetime. Something that directed his focus away from the _too fullness_ and the _hollowness_ that hid behind it.

Mycroft’s last years at Hogwarts were therefore used to refine the basic concept of his plan and to find a balance between the fact that there existed the Ministry of Magic alongside a Parliament.

The Ministry of Magic had a simple structure and was straightforwardly designed to serve a purpose it was at once too understaffed and too presumptuous to manage. Wizarding England had a small population, at least compared with its muggle counterpart, yet there were magical creatures to police, a whole society to keep hidden, and laws to manage. The small population at the same time meant there was little dissent, little innovation, and little dynamic. Society maintained a sleepy pace. The isolating nature of the state at once preserved tradition and fed stagnation.

Mycroft concluded that if he took a career path through the ministry, he would be able to control it in a foreseeable amount of time. Yet, also like the child that would come after him, it was immediately apparent to him that doing so upfront would not serve his purpose. For one, the Minister of Magic was elected. The time in office was limited. For another, there was far too much spotlight on the position and far too many restrictions that needed to be worked around if he wanted to be as effective as he needed to be.

Unfortunately, the small size meant at the same time that there were no secret agencies or departments that, due to their nature, would have far more liberty. Lending a ‘guiding hand’ on matters of state was only feasible if the public didn’t come to complain to him about all their little worries and irritations that were in the grand scheme nonsensical.

That meant that on the one hand, he could find himself another position and deal under the table with it or…

…invent a department that suited his purpose. It was then just a matter of getting it authorized by a minister, which was just a matter of convincing said minister that it was necessary. The threat of Lord Voldemort on the rise would certainly lend credence to that. And _then_ , it was just a matter of leading whichever minister was in office by the nose.

Mycroft was fully confident in his skill to manage as much. The general populace was quite simple after all. (Now, if Headmaster Dumbledore suddenly decided he wanted to be Minister of Magic, then it might be a tad more difficult, but, again, the more difficult it was, the better for Mycroft’s longevity prospects.)

Which brought him to the other, not insignificant fact. Namely, that there were two governments in this nation. Only one side was aware of both. That was an imbalance of power that more or less worked so far, but that left millions of people vulnerable by proxy of their head of state, whose hands were tied in certain matters. Even though that could easily be to the disadvantage of both societies. The broad-scale destructiveness of muggle warfare showed as much. The Statue of Secrecy had its purposes, but that purpose was far from what the wizarding society thought it was.

Mycroft only needed to entertain a thought experiment with a WWII scenario had either side had wizards at their disposal.

Simultaneously, picture what wizarding warfare would look like if there were things like poison gas, bombs, machine guns.

Moreover, and _crucially_ , ideology knew no borders, races, or societies. Ideology could spread like a fire that could not be stamped out. One only needed to look at that to realize how precarious the balance between Britain’s societies, as well as between the nations of the world, was. 

And, consequently, how vulnerable they left themselves by their lack of cooperation.

There was quite a bit of work to do to ensure that it was impossible that the British nation could topple form one day to the next. As his mother and brother lived in Britain, such a fragile state would not do after all. 

By the time Mycroft left Hogwarts, he was quite satisfied with his draft. He began the tedious task of skipping through ranks in the ministry whilst neglecting to mention that he was simultaneously introducing himself to the prime minister and discussing the problem with someone who had the global awareness to grasp the danger. A few instances of proving himself later and he was grated his first subordinates on the one side and a voice that was gaining ever more weight behind closed door on the other.

Quite pleased with his achievements and the positive effect it had on his psyche, Mycroft did what he could to instil the same cognizance in his brother, unwilling to see him waste away his potential.

“Always keep busy.” Mycroft lectured him so often that the words felt imprinted into his tongue. “Always work towards a greater purpose. Something immaterial, something that doesn’t end. Never let that purpose slip from your mind. Not even in your sleep.”

“That explains _so much_ about your neurotic habits,” was always Sherlock’s smart-mouthed reply, more often than not accompanied by an utterly juvenile eye-roll the older he got. 

Mycroft tried to instil in him how important it was that he fixate on something unbreakable, something abstract, or even metaphysical to the point that the horrible overflowing emptiness of the world, the existential dread caused by living, the ultimate _futility_ of everything, could not shake him.

Their family had a tradition of always taking the wife’s name, likely also an attempt at escaping the curse of their genius, but that had protected not a one of them from being so utterly _singular_ that any hope of fitting in with their ‘peers’ was less substantial than mist in the wind. Dedicating his life to something that could never be grasped might not be what other brothers would advise their siblings to do to find happiness, but that was only fair as Mycroft cared less about happiness and more about sanity. He had his priorities straight. 

Sherlock, in typical, contrary, aggravating little brother fashion took Mycroft’s well-intentioned, brotherly advice, and smashed it to bits.

Then, from the shards, he picked out the pieces that he liked best and rearranged them into a picture that was only vaguely related to what Mycroft had been trying to teach him _for his own sanity’s sake_ (and life).

Sherlock did not find some overarching goal like, for example, magical creature equality rights, or, say, devoted himself to discovering the origin of magic or _whatever_.

No, instead he selected puzzles. Mysteries. _Cases_. Concepts that were in praxis as short-lived as flies.

The provision of which, worst of all, was dependent on _outside factors_.

“There’ll always be more mysteries, so shut up Mycroft. You don’t hear me judging you for wanting to become the British government, do you?”

Mycroft, who did, in fact, have to suffer through snide comments about politics every time they saw each other, swallowed any tell that might give Sherlock the satisfaction of having gotten a rise out of him.

This marked another time where Mycroft saw years stretching out before him as if written in a book. Sherlock would jump from one mystery to the next and be in freefall the whole time in between. Not in control. Careless. Reckless. Wasteful with himself. (And Mycroft would be struck by anxious worry _each time_.) 

But no matter how much Mycroft argued that Sherlock was all but consigning himself to a future precariously similar to their father’s, his mind would not be changed. (Sherlock, let it be said, was a wilful, irreverent child and only got more tempestuous with age.)

Where Mycroft valued long-term stability, Sherlock preferred the high of the moment, and maybe _that_ was what had driven their ancestors to the grave. Not the inability to find another way, but the un _willing_ ness.

For years, Mycroft worried what would become of his little brother, a feeling not unlike dread at the back of his neck, but once Sherlock made a decision, he did not tolerate meddling. Not even from their mother, for whom he at least _tried_. The strings allowing Mycroft control over Sherlock and his life were reduced to but a handful, which was reason enough for him to watch them _closely_.

Which was why, when Sherlock went to Hogwarts and their mother mused pleased but bewildered to Mycroft that _their Sherly had made a friend_ as apparently his first letter home talked about nothing but this person, Mycroft wasted no time investigating. When he inspected the letter himself, he found only a few obligatory degrading comments here and there about the lessons and the material but not even a whisper of a complaint about the boarding school system, which had been the biggest sticking point before Sherlock left the house.

The letter was _Liam this, Liam that, Liam, Liam, Liam_.

William James Moriarty then: terribly intelligent, clever enough to be smart about it, and in possession of the _common sense_ that Sherlock sorely failed to care about. Allowing for the eccentricities of a brilliant mind, there was nothing odd about him and Mycroft saw no reason to interfere with Sherlock finding another fixation.

Mycroft had made a mistake.

William James Moriarty now: _terribly_ intelligent, clever enough to fold perception of him into shape that benefitted him, and so calculatingly logical about the world that common sense was less a quality and more a by-product.

Mycroft had been mistaken to think that someone who possessed a mind that could capture Sherlock’s attention and fixation for years, to the point of reckless _obsession_ , who could match their star-bright brilliance, could ever be normal.

Mycroft had _screwed up_.

The plan the boy – and to Mycroft’s eyes he was a _boy_ – had devised was thoroughly prepared and theorized. Already years in motion. Looking back, Mycroft could all of a sudden pinpoint each of the moves that they had made, could trace the causality through the fibres of this constrained, tiny society; The people that had been disposed of, in what way, for what reason, and how the death was _presented_. If Mycroft looked, he could see the evidence, and he had no doubt that that was part of the reason they were approaching him with their plan _now_.

Even before one word was said, when he’d entered the room and seen that doll-like face with the painted expression, he’d already felt his stomach drop with the realization that the loose strings he kept about Sherlock’s life in hand had at some point been thoroughly cut.

Now, after hearing this plan, all Mycroft could see what his little brother was hurling free through space, unchecked except for his own impulse control, and an addict for all the things that gave him the momentarily relief of a thrill.

Sherlock had mysteries (that were infrequent and unreliable), drugs (that Myrcoft did his darndest to regulate), and this one supposed friend who kept him at arms length. Because that friend was busy spinning the greatest case, the greatest _mystery_ of the era right underneath Sherlock’s nose.

Most likely, that was already part of the reason why Sherlock could not go five sentences about Hogwarts without mentioning ‘Liam’.

Which meant that Sherlock knew, but he didn’t _know_ , and he didn’t _want_ to, not when there was someone out there whose entire being seemed like it was tailored to satisfy his carvings. To know too much would cut that off.

And now here stood that person as the perfect combination of Sherlock’s greatest obsessions – mystery, chase, ‘ _Liam’_ – and proposed a plan that would see him dead in a foreseeable number of years.

_Damn it, Sherly_.

In this situation, what could Mycroft do?

(If Mycroft had wanted to protect his little brother, he should have taken Sherlock out of Hogwarts the moment that first letter arrived.)

They had leverage over each other; Mycroft’s their plan, which they had offered to him as a sign of good will, while theirs was the fact that they knew to come to _him_ to negotiate terms about inciting a revolutionary chance in Britain’s societie ** _s_** when he officially only held a minor position in the ministry.

Mycroft’s hands were effectively tied.

No doubt by design.

Mycroft’s own purpose didn’t disagree with them either – it was a ruthlessly effective plan rooted in logic and mass psychology. Therefore, considering Mycroft’s own position and what he was doing, he had no grounds to object to their plan. For the stability of the nation, he could only agree. That his own little brother was dumb was not enough reason in any world to refuse.

_Damn it, Sherly._

Standing in front of the three Moriarty brothers, their proposal metaphorically on the table between them, Mycroft saw the future painted with strokes so fine, in colors of blood red and glittering gold, that it seemed almost lifelike. The future was a tombstone with Sherlock’s name on it.

And there was _nothing_ Mycroft could do, and not even because his hands were tied by this new chess player, but because _Sherly just was that way_.

Nothing Mycroft had ever done managed to sway him when he was decided on something, no matter how half-heartedly, and his fixation with _William_ James Moriarty was anything but half-hearted.

“I won’t interfere,” he accepted the deal, and going with the design of the plan laid out, Mycroft could infer the rest himself, but he still asked: “Just tell me one thing. What do you plan to do about Sherlock?”

Interesting, the reaction that name could cause. Albert smiled placidly, only not staring at the middle distance because he knew better than to so tellingly absent himself. A muscle in Louis’ jaw twitched from suppressed irritation. William, though. William with his polished smile and polished manners was unreadable. Even to Mycroft. No wonder he got Sherlock hook, line, and sinker. An unsolvable, changeable mystery was his fatal flaw.

“Mr. Holmes possesses quite singular qualities that would be a waste not to take advantage of,” the boy, just a few months out of school, agreed formally. His mouth quirked with an imitation of humor that didn’t reach his eyes. “Almost certainly, we will have him shine the light on the darkness we drag forth.”

The image of a grave solidified in Mycroft’s mind, the path towards it riddled with sweet poison and barbwire pitfalls that Sherlock would not even think of avoiding if doing so would cost him a hint. One way or another, no matter which fork in the road of which short cut, Sherlock was too good to not find the way to the end. Unknowing and then eventually uncaring that he would find only his own grave there because to him, his life mattered less than puzzles. 

Outwardly, Mycroft only scoffed. “You’ll have your hands full with that.”

William’s smile widened, almost diabolical now. Oh, he knew _exactly_ what he was at with Sherlock, and he was looking forward to having him play to his tune.

_Foolish, foolish little brother. Look where your thoughtlessness got you._

Mycroft had made a mistake.

Sherlock would pay for it.

How was he supposed to explain Sherlock’s grave to Mommy?

(Was it any wonder that when years later, a muggle doctor stumbled his way into being Sherlock’s friend – a reasonable, grounded, _non-murderous_ friend – Mycroft immediately pulled the necessary strings to make a legal exception to the Statue for him?

Any excuse, any reason, any motivation at all that Mycroft could find for Sherlock to look at the world and see it as more than a blank canvass that he eagerly waited for his other ‘friend’ to paint masterpiece after masterpiece on.)

(Dr. John H. Watson, to his credit, did his best even without knowing what was at stake.)

**Notes for the Chapter:**

> Mycroft's character design: he is the british government  
> Me: but harry potter fusion -  
> Mycroft's character design: He IS The British Government  
> Me: ...well, I suppose he does seem like the type who can't be too busy...  
> Me: Let's make him TWO governments
> 
> Okay, in all seriousness, I thought about where to put Mycroft and there was just no way, _no way_ that he would have been satisfied with just running the Ministry of Magic. This is a man who does politics, black ops, a bunch of agencies, and [who his own brother refers to as the government](https://fanfox.net/manga/yukoku_no_moriarty/v06/c017/1.html#ipg24) despite the fact that they technically had a queen ruling them. And, well, the Ministry of Magic isn't exactly big. There is no way it would have challenged him. To be clear, though, it's more like he 50% the wizarding government and a rising percentage in the muggle one, so it's a work in progress. 
> 
> On that note, you can see that I put away with the French Revolution Social Experiment stuff because their ancestors are wizards here and as such not involved with muggle society in any way, and even if they were, since they aren't subject to muggle law and the Crown has lost power since the Victorian age, who exactly should Mycroft answer to to make up for that? In a hp fusion au that background made no sense, so I left it out, which has consequences I took the liberty to interpret. I have no idea if Doyle's stories ever mentioned anything about their father or their family as a whole, so it's free real estate for me. Driven to an early grave by their genius they therefore are. 
> 
> In case there is some confusion, Mycroft is not a seer or anything. Him seeing the future just refers to calculating the future so precisely that it seems like he can already see the end scene. That's also something William is very good at (he makes a career of it after all). Sherlock on the other hand has no interest in that.


	11. a study in pink

“This is the victim,” the man in the funny clothes said, pushing the picture over the table for Sherlock to take a look. The side-eye John earned for being allowed to see moving pictures was very much noted. John valiantly ignored it.

Sherlock meanwhile gave the picture a scrutinizing look. “Is the original crime scene still intact?”

The man’s stern and hard appearance only grew more severe. “It happened in the middle of the Ministry, Mr. Holmes. What do you think?”

Sherlock’s expression grew annoyed. “Not to mention how long you took to finally give in and seek me out, oh, I’m aware. But there’s always a chance that some of you grew a few braincells in the time I wasn’t looking,” he grumbled back, and the offhand way he said it only made it more insulting.

John was hard pressed to hide a smile. If this man were Lestrade, then John would try to play peacemaker but Lestrade did not look at him and dismiss him as a non-factor for no reason other than that he didn’t have a wand.

The Auror narrowed his eyes at Sherlock. “The victim was heading home from work when she slipped on a wet floor and fell down the stairs and hit her head. The investigation so far has revealed the anti-slipping charms on her shoes were faulty, something that cannot be led back to a source as there is no telling for how long they have been like that – she may have bought them faulty.”

“Yeah, that’s no proof she was murdered,” pointed Sherlock out, eyebrow lifting. “You generally don’t bother to investigate deaths unless there was some evidence of dark magic.” The ‘you uncreative idiots’ was not voiced but John was not the only one who picked up on it, going by the twitch of the magical policeman’s eyebrow. “So, where is the dark magic?”

The other man gritted his teeth. With great, pained reluctance, he admitted, “the Minister insists.”

Sherlock stared at him and snorted. He tossed the photo back on the table with a disgusted flick of his wrist. “You know where the door is,” he said, watching the other man’s face spasm, and only then leaned forward with a razor-sharp glare, no excited smirk in sight. “Or that is what I would like to tell you. I work cases – I’m not a lapdog the Minister can pressure into giving him results...Fortunately for you, I’ll take this request, though.”

The men glared at each other with barely hidden mutual contempt. John held his breath. Sherlock jerked his head in the direction of the door.

The older man rose. “I’ll send one of my men by.” He flicked his wrist and produced a folder, presumably with all the information they had.

“I don’t need an escort.”

“You’ll take one if you want access to places a civilian has no business being,” volleyed the older man back, unimpressed. John vaguely wondered if he ought to introduce him to Lestrade, though the magic/non-magic may prove an issue there.

Sherlock’s glower became sullen. “Get out.” The man clearly did so with pleasure, closing the door behind himself far louder than necessary. John sighed, tension leaving him as a meaningful crack sounded from the staircase, and he turned to Sherlock, opening his mouth when Sherlock cut him off.

With a burst of delighted, excited laughter. “Hell yes,” he said, snatching the photo of the crime scene back up. “Oh, this is gonna be great.” In typical Sherlock fashion, however, he refused to elaborate and given the almost child-like, blinding enthusiasm he threw himself at the files with, John bit his tongue before he could ask. Interrupting Sherlock in this kind of mood stood a good chance to earn you afoul temper after all, as well as genuine irritation for needing ‘every little thing’ explained.

John thought for himself for a while. Sherlock did have the tendency to be excited about murders, especially if they were tough ones, however distasteful it was to take delight in someone’s death. There was no helping that.

On the other hand, that meant he probably already had a reason to consider this case a murder and not an accident – a reason that was apparent to him but no one else, which was nothing strange in itself.

John gave up. “What’s off about a woman slipping down wet stairs and hitting her head?”

Luckily, Sherlock seemed predisposed to a good mood today. “Oh, as much as magical people pretend they’re so above the little accidents of daily life, they’re actually not. It could very well be just that,” he explained with a sharp-edged grin. “It’s the victim that’s off.”

John picked up the photo of the dead woman. Plump, short, not blessed with natural beauty, and with an unfortunate tendency to wear way too much pink. Nothing stood out to him. Was there some magical context he was missing? “Who was this woman?”

“Someone who fits the victim profile to a T,” replied Sherlock with a grin as though that was supposed to be all the explanation necessary. Unfortunately, it was. Sherlock ever only used ‘the,’ singular and specific, to refer to one case. He was gleefully flapping a piece of paper in front of John’s nose as well. “A history of discrimination and racism. Someone who takes advantage of her own power to lord it over others. A voice so bigoted that she was too much for even the populist purist fractions.”

That explained Sherlock’s unshakably good mood, then. “You think she was murdered by the Lord of Crime.” John briefly skimmed the text, though again all the magical terms and references didn’t mean much to him.

“I think there is a very good chance that he may have a hand in it,” corrected Sherlock brightly. “The woman had no shortage of enemies. If she was murdered, this is going to be an interesting one.” There was a spark in his eyes that could easily blaze into the sort of fire that razed everything that stood between him and the truth to the ground.

John was torn between worrying about the enthusiasm he bestowed upon any hint of a ruthless, genius mastermind and being excited himself to see another case reveal its every secret to Sherlock’s probing. Especially since it was a magic case. Sherlock would hate to hear it, but John found magic to be quite curious and amusing. (Mindwiping aside.) (He still hadn’t quite decided how to go about writing about those cases. Or rather, he had already written something, but he wasn’t sure what to do with the finished draft now…)

“Alright, John, let’s go,” Sherlock declared, gathering the file he’d picked apart back into some resemblance of order before contrarily – for someone who did not know him – abandoning the thing on the table instead of taking it with him as he strode towards the door. He liked to have files available for double-checking but generally he memorized everything at first look, so the file of one Dolores Umbridge would probably remain somewhere within easy sight until the case was solved. Even if that meant the file served as a saucer. Not that this one did. (Yet.) But it had happened before.

“Where are we going?” John asked, getting his jacket. “Aren’t we supposed to wait here for one of the magic policemen?”

“Who cares?” dismissed Sherlock carelessly. “They can come looking for us, I’m not waiting on their red tape. Not like anyone needs special permission to enter the Ministry of Magic.”

John mouthed ‘Ministry of Magic’ to himself and tried to keep all excitement from showing – he failed of course, this was Sherlock Holmes he was dealing with, but for all that his expression twitched, he at least didn’t call him out on it.

**Author's Note:**

> At this point, I would also like to mention that I'm taking prompts for this in the reviews. If you have scenes you would like to see written, describe them in as much detail as possible. Again, I'm not making _any_ promises in any way at all, though, sorry.
> 
> Prompts:  
> \- John and William meeting: wip  
> \- William pov: wip


End file.
